One-Hit Wonder Potential of Each 2017 MLB Breakout Star

Joel Reuter@JoelReuterBRFeatured ColumnistSeptember 26, 2017

One-Hit Wonder Potential of Each 2017 MLB Breakout Star

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    Seth Wenig/Associated Press

    How much stock should you put in a breakout season?

    It's a question fantasy baseball owners ask themselves each spring and it's one we're going to try our best to answer here in the waning days of the 2017 MLB season.

    Ahead we've lumped each notable 2017 breakout player into three different categories:

    • One-Hit Wonders: These guys are facing significant regression and there's a very good chance they won't come close to matching the performance we've seen this year.
    • Regression Candidates: These guys also look like regression candidates but not quite at the same drastic level as the one-hit wonders. They still have promising futures, but expecting them to duplicate or build off of this season's numbers might be asking too much.
    • Legitimate Stars: These guys are the real deal. The 2017 numbers are sustainable and in some cases just the start. 

    Players were assessed based on a number of advanced metrics as well as their past track records and developmental expectations.

            

    Note: To trim the field a bit, a player had to have at least a 2.0 WAR this season to be considered for inclusion. As a result, Trey Mancini (1.9), Jose Berrios (1.8), Luke Weaver (1.8), Eddie Rosario (1.4) and Rafael Devers (1.2) were among the notable exclusions.

    Jimmy Nelson (shoulder surgery) and Michael Conforto (shoulder surgery) were also excluded after their seasons were cut short due to significant injuries. Both have star-level upside but will need to prove healthy.

One-Hit Wonders (Pitchers)

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    Jose Urena
    Jose UrenaAssociated Press

    Kyle Freeland, Colorado Rockies
    27 GS, 11-10, 4.03 ERA, 125 ERA+, 1.47 WHIP, 107 K, 152.0 IP, 3.4 WAR

    A vastly improved starting rotation has allowed the Rockies to go from 87-loss team to legitimate contender, and left-hander Kyle Freeland has played a significant part in that.

    His 3.4 WAR is tops among rookie pitchers and his 125 ERA+ ranks 10th among NL pitchers with at least 150 innings.

    However, with hittable stuff (.279 BAA) and a 4.58 FIP, he's walked a dangerous line and could quickly fall behind the likes of Jon Gray, German Marquez, Antonio Senzatela and Jeff Hoffman on the staff.

                  

    Jose Urena, Miami Marlins
    26 GS, 14-6, 3.55 ERA, 115 ERA+, 1.22 WHIP, 107 K, 159.2 IP, 2.4 WAR

    There's probably not a bigger regression candidates among pitchers this season than Jose Urena.

    The 26-year-old ranks 10th in the NL with a 3.55 ERA and his .231 BAA is good for seventh.

    However, his .243 BABIP (second-lowest among qualified starters) and 5.00 FIP paint a better picture of what to expect going forward.

One-Hit Wonders (Hitters)

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    Avisail Garcia
    Avisail GarciaTed S. Warren/Associated Press

    Avisail Garcia, Chicago White Sox
    130 G, .331/.379/.504, 164 H, 46 XBH (18 HR), 80 RBI, 70 R, 4.4 WAR

    Avisail Garcia was a .258 career hitter and a non-tender candidate last offseason, but the Chicago White Sox brought him back and he's rewarded them with a breakout season.

    But his .331 averagesecond in the ALis propped up by a .394 BABIP that is the highest of any qualified hitter and his walk rate has actually declined (7.5 to 5.6 percent) amid that surface breakout.

            

    Scooter Gennett, Cincinnati Reds
    135 G, .298/.346/.547, 131 H, 52 XBH (27 HR), 94 RBI, 79 R, 2.6 WAR

    Has there been a more surprising power surge than Scooter Gennett?

    The 27-year-old entered the season with 35 home runs and a .738 OPS in 1,637 career plate appearances and he was claimed off waivers from the Milwaukee Brewers in March.

    His OPS has skyrocketed to .893 this season and he's slugged 27 home runs in 474 trips to the plate, but an unusually high 21.8 percent home run per fly-ball rate likely won't be sustainable given his modest raw power. Expect his 2017 campaign to be an outlier, not the new norm.

           

    Tommy Pham, St. Louis Cardinals
    122 G, .310/.410/.526, 132 H, 46 XBH (22 HR), 71 RBI, 91 R, 23 SB, 5.9 WAR

    If the St. Louis Cardinals are smart, they'll make every attempt to sell high on Tommy Pham this winter.

    His .374 BABIP is second among qualified hitters and his 26.8 HR/FB percentage ranks sixth and puts him in a similar position as the aforementioned Gennett, given his track record and physical tools.

    With Dexter Fowler and Stephen Piscotty signed long-term, Randal Grichuk still under control and prospects Harrison Bader, Tyler O'Neill and Magneuris Sierra all knocking on the door, he's a prime candidate to be flipped.

           

    Chris Taylor, Los Angeles Dodgers
    136 G, .287/.355/.498, 144 H, 59 XBH (21 HR), 69 RBI, 84 R, 17 SB, 4.8 WAR

    A player with the defensive versatility of Chris Taylor will always carry some level of value on a roster, but expecting anything close to his 2017 offensive numbers going forward will be wishful thinking.

    The 27-year-old has a .362 BABIP that ranks sixth among qualified hitters, and luck has already started to catch up to him as he's hitting just .202/.253/.348 in September.

Regression Candidates (Pitchers)

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    Corey Knebel
    Corey KnebelAssociated Press

    Chase Anderson, Milwaukee Brewers
    24 GS, 11-4, 2.81 ERA, 156 ERA+, 1.12 WHIP, 128 K, 134.1 IP, 3.8 WAR

    Chase Anderson has gone from rotation afterthought to legitimate No. 2 starter on a contending Milwaukee Brewers team this season.

    An uptick in fastball velocity (92.2 to 93.7 mph) coupled with an improved ability to get opposing hitters to chase outside the zone (24.6 to 30.1 percent) has led to a breakout season.

    The 29-year-old has yet to eclipse the 160-inning mark in his career and his 3.55 FIP is a good sign that some regression awaits next season, but he's established himself as a key piece of the Milwaukee rotation.

           

    Zack Godley, Arizona Diamondbacks
    24 GS, 8-8, 3.20 ERA, 150 ERA+, 1.11 WHIP, 158 K, 149.0 IP, 4.7 WAR

    Zack Godley was as far off the "breakout" radar as any player in the league after posting a 6.39 ERA in 74.2 innings of work in 2016.

    However, his ability to keep hitters off-balance has made him a different pitcher this season.

    He throws a curveball (34.5 percent), sinker (32.8 percent) and cutter (24.7 percent) without relying heavily on any one pitch, and he also sprinkles in the occasional changeup (7.8 percent).

    Since he pitches more on feel than stuff, he's likely reached his ceiling, but a 3.27 FIP gives reason to believe he can come close to duplicating his 2017 success. 

           

    Corey Knebel, Milwaukee Brewers
    73 G, 37/43 SV, 1.60 ERA, 1.16 WHIP, 4.9 BB/9, 14.9 K/9, 3.8 WAR

    Trading away Tyler Thornburg during the offseason opened the door for Corey Knebel to step into the closer's role for the Milwaukee Brewers, and he turned that opportunity into an All-Star season.

    Improved fastball velocity (96.2 to 97.8 mph) to go along with a lethal curveball (.148 BAA, .016 ISO) have helped him rack up 121 strikeouts in 73 innings.

    However, his 13.5 percent walk rate is seventh-highest among pitchers with at least 50 innings and a 92.5 percent strand rate might not be repeatable.  

           

    Brad Peacock, Houston Astros
    33 G, 20 GS, 12-2, 2.98 ERA, 133 ERA+, 1.20 WHIP, 159 K, 127.0 IP, 3.0 WAR

    Brad Peacock entered spring training out of options and in danger of losing his spot on the roster as he sported a 4.57 ERA in 263.2 innings spanning five seasons.

    The 29-year-old ended up winning a spot in the bullpen, and by May, injuries had opened a spot in the rotation. 

    In 20 starts, he's gone 9-2 with a 3.21 ERA, 1.23 WHIP and 133 strikeouts in 106.2 innings.

    A sharp spike in his swinging strike rate (7.9 to 12.0 percent) speaks to his improved stuff. He's yet to prove himself over a full season of innings and he's reached his ceiling given his age, but he now looks like a far more significant piece of the puzzle in Houston than at this time a year ago.

            

    Alex Wood, Los Angeles Dodgers
    26 G, 24 GS, 15-3, 2.71 ERA, 154 ERA+, 1.04 WHIP, 150 K, 146.1 IP, 3.2 WAR

    After starting the season in the bullpen, Alex Wood went 11-0 with a 1.56 ERA and 0.88 WHIP in 14 starts and two relief appearances in the first half to earn a spot on the NL All-Star team.

    However, the 26-year-old was shellacked in his first start of the second half (4.2 IP, 9 H, 7 ER), and he's gone 4-3 with a 4.37 ERA and 1.27 WHIP in 10 starts since the break.

    Expect him to land somewhere in between and be a solid middle-of-the-rotation arm going forward.

Regression Candidates (Hitters)

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    Orlin Wagner/Associated Press

    Paul DeJong, St. Louis Cardinals
    101 G, .280/.321/.524, 47 XBH (24 HR), 60 RBI, 51 R, 2.4 WAR

    It's hard to imagine the St. Louis Cardinals even sniffing wild-card contention without the unexpected contributions of Paul DeJong.

    The power is legit and he's been better than expected defensively at shortstop (1 DRS, 3.7 UZR/150), so the everyday job will be his going into next season.

    However, his lack of plate discipline (4.8 percent walk rate) is something that pitchers are going to find a way to use against him and a .341 BABIP might regress as well due to his lack of speed.

          

    Marwin Gonzalez, Houston Astros
    128 G, .296/.367/.521, 54 XBH (22 HR), 82 RBI, 63 R, 4.0 WAR

    Move over, Ben Zobrist.

    Marwin Gonzalez has at least 19 games at all four infield spots and he's actually seen most of his action in left field. 

    Along the way, he's set new personal bests across the board offensively and his versatility has been invaluable to a first-place Houston Astros team.

    The fact that his hard-contract rate (33.2 to 32.6 percent) and soft-contract rate (14.7 to 18.7 percent) have actually trended in the wrong direction gives a reason for pause. He's good, but has it just been the perfect storm this season?

          

    Rhys Hoskins, Philadelphia Phillies
    44 G, .278/.409/.682, 25 XBH (18 HR), 46 RBI, 34 R, 2.2 WAR

    We're already seeing the beginning of what was an inevitable regression for Rhys Hoskins.

    • First 34 games: 147 PA, .314 BA, 1.247 OPS, 18 HR
    • Last 10 games: 39 PA, .152 BA, .524 OPS, 0 HR

    The league is adjusting to him and now it's time for him to make further adjustments of his own.

    He's hit 85 home runs between the minors and majors the past two seasons, so his power is legit and a 16.8 percent walk rate speaks to his solid overall approach.

    He's capable of being an above-average everyday player, but he's not quite the superstar he looked like in the early going.

           

    Logan Morrison, Tampa Bay Rays
    144 G, .243/.352/.515, 120 H, 59 XBH (37 HR), 83 RBI, 73 R, 3.6 WAR

    Logan Morrison has flashed some intriguing power in the past, including a 23-homer season as a 23-year-old in 2011, but nothing like what he's done this year on a one-year, $2.5 million deal with the Tampa Bay Rays.

    An improved walk rate (9.3 to 13.6 percent) and hard-contact rate (34.2 to 37.3 percent) speak to a better approach, and he's fully bought into the idea that more flyballs (34.7 to 46.3 FB%) mean more home runs.

    However, at this point, the 30-year-old is more likely to see 2017 as a career year than a launching point for better future numbers and legitimate stardom.

             

    Matt Olson, Oakland Athletics
    59 G, .259/.352/.651, 26 XBH (24 HR), 45 RBI, 33 R, 2.9 WAR

    Even if he were playing his games next season on a Little League field, Matt Olson might have a hard time maintaining a 41.4 percent HR/FB rate.

    He has legitimate 60-grade power or better and he's always been willing to work a walk, with a .364 on-base percentage and a pair of 100-walk seasons in the minors.

    But so much of his value is tied to his over-the-fence power that the inevitable regression in his home run rate will ultimately take a bite out of his star power.

    With regular at-bats, he can be a perennial 25-30 home run threat with a strong enough on-base percentage to offset his low batting average.

           

    Domingo Santana, Milwaukee Brewers
    146 G, .277/.370/.498, 56 XBH (28 HR), 80 RBI, 84 R, 15 SB, 2.8 WAR

    Domingo Santana has improved everywhere you expect to see a young hitter who's figuring things out improve, and his 12.3 percent walk rate will make him a valuable on-base threat if he can maintain that going forward.

    It's his power that raises some eyebrows.

    His 30.1 percent HR/FB rate trails only Aaron Judge (35.2 percent) and Giancarlo Stanton (34.1 percent) among qualified hitters. Santana has some pop, but he's not on the same level as those guys in terms of raw power.

    Santana looks like a long-term piece as he's still just 25 years old, but expecting him to be a regular threat for 30 homers might be asking too much.

          

    Jonathan Schoop, Baltimore Orioles
    155 G, .299/.343/.516, 67 XBH (32 HR), 105 RBI, 91 R, 5.2 WAR

    Jonathan Schoop hinted at bigger and better things last season, when he posted a .752 OPS with 38 doubles and 25 home runs to solidify himself as one of the best offensive second basemen in the league.

    He's taken things to another level this season and could wind up finishing in the top 10 in AL MVP voting.

    So are his 2017 numbers the new norm?

    His 5.2 percent walk rate is concerning, and his BABIP climbing from .305 to .337 is a good indication of a contact-reliant player whose batting average is benefiting from some good luck.

    There's reason to think he can be a regular threat for 30-plus home runs, but expect to the triple-slash numbers to dip going forward.

Legitimate Stars (Pitchers)

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    Bill Kostroun/Associated Press

    Archie Bradley, Arizona Diamondbacks
    61 G, 25 HLD, 1.41 ERA, 0.96 WHIP, 2.3 BB/9, 9.8 K/9, 3.9 WAR

    A future setup role might not have been what the Arizona Diamondbacks envisioned when they took Archie Bradley with the No. 7 overall pick in 2011, but it's hard to argue with the results.

    The 25-year-old leads all relievers—closer or otherwise—with a 3.9 WAR this season.

    The full-time move to the bullpen has given his fastball velocity a shot in the arm (93.4 to 96.5 mph) and allowed him to ditch his changeup, which had been a largely ineffective third offering behind his plus curveball.

    He should have a clear path to the closer's role next season with Fernando Rodney headed for free agency, though a return to the rotation is not out of the question. Either way, his future looks bright.

            

    Luis Castillo, Cincinnati Reds
    15 GS, 3-7, 3.12 ERA, 141 ERA+, 1.08 WHIP, 98 K, 89.1 IP, 2.6 WAR

    It's a small sample size, but Luis Castillo looks like the best of the bunch in a deep stable of young arms in Cincinnati.

    The 24-year-old came over from the Miami Marlins during the offseason in exchange for Dan Straily and he's been brilliant since joining the rotation in mid-June.

    Last time out, he allowed just four hits and one earned run while striking out 10 against a good Milwaukee Brewers lineup.

    He's always had good command of his electric fastball (97.9 mph) and his slider has been lethal (.091 BAA, .021 ISO). Throw in a solid 3.73 FIP and he'll be one of the more intriguing second-year pitchers to watch in 2018.

           

    Chad Green, New York Yankees
    37 G, 7 HLD, 1.90 ERA, 0.74 WHIP, 2.2 BB/9, 13.7 K/9, 2.6 WAR

    The New York Yankees already had one of the best bullpens in the league even before adding Tommy Kahnle and David Robertson at the trade deadline, and the emergence of Chad Green was a big reason why.

    Even in a small sample size last year, it was clear he was better suited as a reliever:

    • As starter: 36.1 IP, 5.94 ERA, 1.51 WHIP
    • As reliever: 9.1 IP, 0.00 ERA, 0.96 WHIP

    His fastball/slider pairing has led to 102 strikeouts in 67.1 innings this season, and he's pitched beyond one inning in 27 of his 36 relief appearances. And his 1.74 FIP is actually better than his 1.90 ERA.

    In this age of hybrid relievers, he's been one of the most underappreciated players of 2017.

           

    Felipe Rivero, Pittsburgh Pirates
    71 G, 19/21 SV, 14 HLD, 1.72 ERA, 0.90 WHIP, 2.5 BB/9, 10.6 K/9, 2.5 WAR

    Props to the Pittsburgh Pirates front office for turning free-agent-to-be Mark Melancon into hard-throwing Felipe Riverowho has control through the 2021 season—last summer.

    Tony Watson and Juan Nicasio both took a turn in the closer's role before Rivero finally seized the job in mid-June and hasn't looked back since.

    His velocity plays from the left side and Rivero can bring it with a 98.8 mph average fastball. The fact that he pairs that with a virtually unhittable slider (.067 BA, .022 ISO, 24 K) makes him elite.

    The 26-year-old has as much upside as any young reliever in the game.

          

    Luis Severino, New York Yankees
    30 GS, 13-6, 3.03 ERA, 151 ERA+, 1.05 WHIP, 221 K, 187.1 IP, 5.2 WAR

    As good as the overall numbers look for Luis Severino this season, he's been at another level entirely the past few months.

    He exited his last start after just three innings as the result of a high pitch count, but prior to that, he had gone 8-2 with a 2.23 ERA, 0.93 WHIP and a .176 opponents' batting average over a 13-start stretch.

    With a 3.08 FIP and improved peripherals across the board, there's nothing to suggest this season has been anything short of the emergence of a new ace in the Bronx.

Legitimate Stars (Hitters)

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    Nick Wass/Associated Press

    Cody Bellinger, Los Angeles Dodgers
    126 G, .273/.356/.599, 126 H, 68 XBH (39 HR), 94 RBI, 86 R, 10 SB, 4.2 WAR

    We're seeing exactly the kind of production evaluators projected for Cody Bellinger.

    They just expected it to come closer to his age-27 season, as opposed to his age-21 season and rookie year.

    Bellinger was arguably the top power prospect in baseball heading into the season after a 26-homer performance in the upper levels of the minors as a 20-year-old, and he's delivered.

    He hasn't missed a beat since getting the call on April 25, and there's no reason to think he'll be anything but one of the league's most productive middle-of-the-order bats for the next decade-plus.

          

    Andrew Benintendi, Boston Red Sox
    145 G, .275/.358/.429, 152 H, 46 XBH (19 HR), 88 RBI, 81 R, 19 SB, 2.7 WAR

    The favorite to win AL Rookie of the Year honors heading into the season, Andrew Benintendi has been largely overshadowed by the exploits of Aaron Judge.

    After a somewhat slow start, he's hitting .303/.389/.495 with 12 doubles and eight home runs since the beginning of August and that's a good indication of what to expect going forward.

    An 11.0 percent walk rate and 16.6 percent strikeout rate speak to his advanced approach and elite-caliber hit tool. 

    The 23-year-old has a chance to be a perennial contender for the batting title and a 20/20 player in the process.

          

    Byron Buxton, Minnesota Twins
    136 G, .253/.316/.419, 113 H, 36 XBH (16 HR), 50 HR, 68 R, 27 SB, 5.1 WAR

    The perception of Byron Buxton as a "star" depends on whether you consider guys like Andrelton Simmons, Jason Heyward and Kevin Kiermaier to be stars.

    The 23-year-old ranks second among all outfielders with 24 DRS and his 13.9 UZR/150 is good for fifth, giving him a 2.8 dWAR that trails only Simmons (4.1) and is tied with Tucker Barnhart (2.8).

    His offensive game is still a work in progress, but he's been roughly a league-average performer with a 95 OPS+ and he's made an impact on the bases with 27 steals in 28 attempts.

    Even if he never takes that next step at the plate, he's already an elite defender providing star-level value.

            

    Willson Contreras, Chicago Cubs
    113 G, .275/.351/.504, 101 H, 42 XBH (21 HR), 73 RBI, 49 R, 3.7 WAR

    If he hadn't missed 29 games with a hamstring injury, Willson Contreras might be smack dab in the middle of the NL MVP conversation.

    The 25-year-old came out of the All-Star break on fire, posting a 1.017 OPS with eight home runs and 22 RBI in 18 games before hitting the disabled list.

    Along with his offensive exploits that have immediately made him one of the game's most productive backstops, he's also a stellar defender.

    The fact that's he's thrown out just 27 percent of base stealers is largely a result of his pitching staff and he's tallied 6 DRS with an 11.9 DEF value that ranks seventh among all catchers.

    After deferring to David Ross for much of the postseason a year ago, he'll be running the show in 2017.

          

    Joey Gallo, Texas Rangers
    138 G, .206/.330/.525, 89 H, 59 XBH (38 HR), 76 RBI, 81 R, 3.0 WAR

    We've never seen a player quite like Joey Gallo before.

    He hitting just .206 with 89 hits in 512 plate appearances.

    However, that hasn't stopped him from being a 3 WAR player and ranking among the top 20 in the AL with an .855 OPS.

    The 23-year-old has legitimate 75-grade power and belongs right alongside Giancarlo Stanton and Aaron Judge when talking about the best pure power guys in the game.

    He'll be a perennial threat for 40 homers, and as long as he maintains his walk rate (14.1 percent), a batting average hovering around the Mendoza line can be overlooked.

           

    Aaron Judge, New York Yankees
    149 G, .281/.416/.610, 147 H, 73 XBH (48 HR), 105 RBI, 122 R, 7.3 WAR

    Props to Aaron Judge for putting a disastrous month of August in the rearview and leading the offensive charge once again in September.

    The first thing that pops up in any conversation about the mammoth 6'7" slugger is his power and rightfully so, as he'll be launching balls out of Yankee Stadium for years to come.

    Next up is the strikeouts—202 of them to be exact, a rookie record.

    However, as long as he continues to walk at an elite rate (18.3 percent), he can navigate a good deal of swing-and-miss in his game.

    There are actually a lot of similarities from a peripheral standpoint to be drawn between what Judge is doing this season and what Kris Bryant did as a rookie in 2015. If Judge can make some similar adjustments, he still has a lot of room to improve.

           

    Travis Shaw, Milwaukee Brewers
    139 G, .274/.348/.522, 142 H, 66 XBH (31 HR), 99 RBI, 79 R, 4.2 WAR

    The Boston Red Sox spent a good portion of the 2017 season searching for an answer at third base, something they had right in front of them prior to shipping Travis Shaw to the Milwaukee Brewers for reliever Tyler Thornburg.

    After posting a .726 OPS with 34 doubles and 16 home runs last season, Shaw has really come into his own as a middle-of-the-order threat for a contending team.

    Improvements in his hard-contact (33.3 to 37.4 percent) and soft-contact (21.9 to 15.5 percent) rates help lend some credence to his breakout performance at the plate, and he's also an above-average defender at the hot corner.

    He's every bit as good right now as someone like Kyle Seager. 

           

    Justin Smoak, Toronto Blue Jays
    153 G, .275/.360/.542, 67 XBH (38 HR), 89 RBI, 84 R, 3.1 WAR

    Justin Smoak looks like a safer bet to come close to duplicating his 2017 production than fellow breakout first baseman Logan Morrison, thanks in large part to the advantage he holds in the plate discipline department.

    The fact that he cut his strikeout rate considerably (32.8 to 20.2 percent) while also turning in the best power numbers of his career is a great sign, and a .289 BABIP is roughly in line with his career mark.

    The 30-year-old has come out of nowhere this season and breakout performances at that age are always best taken with a grain of salt, but it's tough to poke holes in his production based on his peripheral numbers.

           

    All stats courtesy of Baseball ReferenceFanGraphs and Brooks Baseball and accurate through Sunday's games.