Ranking the Top 10 MLB Prospects Making Waves in Offseason Leagues

While the majority of the baseball world is focused on the stars of today and where they will be playing next season, the stars of tomorrow are honing their crafts in various offseason leagues. 

Over the next few slides, we'll rank the most eye-opening individual performances taking place in the Arizona Fall League. 

It may only be a month's worth of games, but the AFL is often a jumping point for prospects to take that next step. In the 2014 AFL season, New York Yankees slugger Greg Bird used a standout performance to prepare for a call-up to "The Show" the very next season. 

There are numerous prospects following in Bird's footsteps this fall. Fellow Yankee Gary Sanchez, Minnesota Twins outfielder Adam Brett Walker II, Atlanta Braves hurler Lucas Sims and Boston Red Sox first baseman Sam Travis are just a few of the players we'll look at it in the coming slides. 

We'll obviously take statistical information into account, but we'll also take a look at how each prospect's game is progressing. In this case, a player's development is just as important as a small sample size of numbers. 

Let us know what you think about our selections in the comments section below. Which prospects have impressed you this fall? What is a realistic timeline for the following names to reach the major leagues? 

2015 will go down in MLB history as the year of the prospect, so it's fitting that various young players are jockeying for position in the AFL. Let's rank the most impressive of those performances. 

Honorable Mentions

Ray Black, San Francisco Giants

Black has overcome a shoulder injury early in his career to reclaim his elite velocity. Behind a 100-mph fastball, the right-hander has allowed just one earned run and has fanned 12 batters in seven innings. 

Willson Contreras, Chicago Cubs

If not for an untimely hamstring injury, Willson Contreras would find himself on this list. Still, the impressive catching prospect slashed .283/.361/.547 and hit three homers in 14 games. 

Dominic Smith, New York Mets

Smith is another player who has suffered from an injury this fall, but he's still proven to be an attractive prospect. The first baseman slashed .385/.519/.564 in 12 games in the AFL. 

Raimel Tapia, Colorado Rockies

Tapia is a toolsy outfielder that's on the fast track to the big leagues. He's impressed this fall too, hitting .333 with 37 total bases. 

Clint Frazier, Cleveland Indians

AFL Stats: 18 G, .297/.366/.459, 3 HR, 8 RBI, 4 SB, .825 OPS

After being taken with the fifth-overall pick in the 2013 draft by the Cleveland Indians, Clint Frazier has catapulted to the top of MLB.com's prospect list. The talented outfielder is currently ranked as the No. 35 overall prospect in the minors.

The 21-year-old blitzed High-A pitching this season, slashing .285/.377/.465. Frazier flashed the pop (16 HR) and speed (15 SB) scouts covet when looking at outfielders. He's carried that momentum into the AFL, showcasing his complete skill-set in 18 games. 

Because of Frazier's strong finish to the regular season and continued success into the AFL, Jason Lukehart of SB Nation believes the outfielder could be the premier prospect in the Cleveland organization:

"

(Bradley) Zimmer's tremendous first four months of the season have moved him ahead of Frazier on most prospect lists, but given Clint's strong finish to the year (and strong early play in the AFL) and the fact that he's almost two full years younger than Zimmer, I think there's a reasonable case to be made that Frazier is now the team's top prospect. Either way, he looks ready for new challenges, and if he can avoid a slow start in 2016, Red Thunder could find himself in Cleveland as soon as 2017.

"

Frazier's numbers are fantastic, but there are other players who are enjoying better falls. But if his last few months are any indication, there may not be a more talented prospect playing in the AFL than the Indians outfielder. 

Austin Dean, Miami Marlins

AFL Stats: 14 G, .327/.373/.473, 1 HR, 6 RBI, .846 OPS

Austin Dean may not be a big-name prospect, but he's proving to the Miami Marlins he could be one of the club's future table-setters. 

Dean, a former fourth-round draft pick, had a modest 2015 season. At High-A, the 22-year-old hit .268/.318/.366 with 18 SB. He's been much better in the AFL, hitting well over .300 and driving in six runs. 

One of Dean's most promising developments is his improved contact rate. In High-A, he struck out just 13.1 percent of the time, which is a drastic change from his 19.2 percent mark in Rookie Ball in 2012. 

"Dean has a very quick swing, a mature approach and a knack for putting the barrel on the ball," said MLB.com. "He cut his strikeout rate in 2014 and has shown an ability to make adjustments at the plate. He has some raw power, but doesn't get to use it much during games because his swing is geared to produce line drives."

Dean is a table-setter by nature, so the improvement he's shown in plate discipline over the last year is a step in the right direction. He's old for a prospect, but there's reason to believe Dean is starting to figure out how to use his talents to make an impact. 

Josh Hader, Milwaukee Brewers

AFL Stats: 6 G, 14 IP, 0.64 ERA, 18 K, 5 BB

The Milwaukee Brewers cleaned up in the Carlos Gomez/Mike Fiers trade this summer, but Josh Hader's production this fall is nothing but a cherry on top. 

Hader is currently ranked No. 14 in the Milwaukee organization, which is a why he's often the forgotten man among Brett Phillips and Domingo Santana. But Hader is making sure the Brewers appreciate his services.

A starter by trade, Hader posted a 3.04 ERA in 17 starts this past season. In seven Double-A starts, the left-hander fanned more than 32 percent of the batters he faced and recored a sub-3.00 ERA. In the AFL, Hader has a 0.64 ERA in 14 innings in relief outings. Naturally, his velocity has increased due to shorter stints on the mound.

The Brewers aren't going to give up on Hader as a starter, but he's proven he could be a lights-out late-inning option if taking the ball every fifth day doesn't work out. That versatility will only enhance his value, and make him one of Milwaukee's more intriguing prospects entering 2016. 

Sam Travis, Boston Red Sox

AFL Stats: 17 G, .333/.395/.500, 1 HR, 12 RBI, 2 SB, .895 OPS

The Boston Red Sox are loaded with top-tier prospects, which makes Sam Travis a forgotten man at times. But the first baseman is doing his best to stand out from that crowded pack of talented youngsters.

Travis advanced all the way from Rookie Ball to Double-A in 2015, slashing .307/.381/.452 and driving in 78 runs across three different levels. The 22-year-old hasn't stopped hitting in the AFL, as he's slugging .500 and his 36 total bases rank sixth among league hitters.

He may not have the same upside that others in the organization have, but Travis has positioned himself to make a serious run at Boston's first base job as early as 2016. 

"In a system with a lack of depth at first base, Travis figures to be next in line with a possible major league promotion by the end of the next season or beginning of 2017," said Jen McCaffrey of MassLive.com.

Travis is a gifted offensive player who's used the past year to improve his game. His performance in the AFL is just a continuation of a fine 2015 season, which is why he's one of the fastest-rising prospects in the Red Sox organization.   

Nick Travieso, Cincinnati Reds

AFL Stats: 4 G, 3 GS, 17 IP, 2.12 ERA, 17 K, 3 BB

The Cincinnati Reds have a nice crop of young hurlers on the horizon, but Nick Travieso is as hot as any pitcher in the minor leagues. 

Travieso is on a consistent path to the big leagues. In 2014, he went 14-5 with a 3.03 ERA. He led the league in wins and finished sixth in WHIP that season. 

The right-hander spent the majority of 2015 in High-A. While there, Travieso made 19 starts and recorded a 2.70 ERA. In the AFL, the 21-year-old has a 2.12 ERA in 17 innings. Better yet, he has combined strikeout stuff with impressive command (17 K to 3 BB.)

Travieso is rapidly approaching a debut in the major leagues. He has only improved over the course of the last few seasons, and he has proven himself against some of the top hitters in the minor leagues while in the AFL.

He may be Cincinnati's sixth overall prospect, but he continues to exceed expectations as he progresses toward "The Show."

Jeimer Candelario, Chicago Cubs

AFL Stats: 16 G, .349/.382/.683, 5 HR, 13 RBI, 1.065 OPS

The Chicago Cubs have become a pipeline for impressive young sluggers over the last few seasons, and the powerful Jeimer Candelario is the latest youngster to make waves.

Candelario advanced to Double-A in 2015 after spending part of the last two seasons in High-A. After his promotion, the 21-year-old slashed .291/.379/.462 and hit five homers in 46 games. In the AFL, Candelario has shown the same plate discipline and pop that put him on the Cubs radar. 

A switch-hitter, Candelario is one of the more intriguing players in the Chicago system. It's always a positive sign when a young player has a grasp of the strike zone—he walked more than he struck out in Double-A— and that plate awareness only enhances his value to the organization. 

"He's a guy we've always just been waiting to take a step forward," director of player development Jaron Madison told Josh Jackson of MiLB.com. "He's got a good swing from both sides of the plate and he started understanding what he can do for himself, being more aggressive in the count. He'll be first to tell you, pitch selection and being aggressive was the key for him this year."

The 21-year-old is currently the Cubs No. 20 prospect, according to MLB.com. After an impressive 2015 and AFL stint, Candelario won't be that low for much longer. 

Adam Engel, Chicago White Sox

AFL Stats: 17 G, .417/.532/.683, 1 HR, 8 RBI, 9 SB, 1.216 OPS

Adam Engel is known for his speed. In 2015 alone, the 23-year-old swiped 65 bases in High-A. 

But Engel is proving to be more than a demon on the bases. After subpar seasons at the dish, Engel slashed .251/.335/.369 and was consistently on base for his team in 2015.

It's a small sample size, but Engel has developed even further in the AFL. The base-stealing threat is still there, but he's also sporting a ridiculous .532 on-base percentage. 

Engel's goal has been simple: Put together the best at-bat he can each time out. 

“Just quality ABs,” Engel told Alex Smolokoff of Today's Knuckleball. “Just trying to get a feel for what it takes to have a quality AB the most often that I can. Any time you have a quality at bat at the top of the lineup, I think it helps the team out. That’s my job.”

The toolsy outfielder figures to begin 2016 in Double-A. Winter leagues are by no means indicative of how a player will perform throughout the rest of his career, but there's no doubt Engel's stock has risen over the last month. 

Lucas Sims, Atlanta Braves

AFL Stats: 4 GS, 14 IP, 1.93 ERA, 15 K, 3 BB

After a flurry of changes to the major league club, Lucas Sims was shoved out of the way by a handful of freshly acquired minor league arms. But the Atlanta Braves right-hander is proving he's arguably the most talented player in the organization. 

Sims dropped to Atlanta's ninth overall prospect after a subpar 2015 campaign. Between three different levels, Sims posted a 4.37 ERA and struggled to maintain his command. Sims did pitch better down the stretch—he allowed just three earned runs in his last five starts in Double-A—and those in the Braves organization hoped to see him continue that in the AFL.

The 21-year-old has done just that, carrying over that positive momentum he gathered at the end of 2015. Sims has posted a 1.93 ERA in four starts, walking only three hitters in those outings. 

The way that Sims has attacked AFL hitters over the last month bodes well for 2016 and beyond. 

“He’s having a great time at this level," Braves Low-A Rome pitching coach Gabe Luckert, who’s in that same role for the AFL team, told David O'Brien of the Atlanta Journal-Constitution. "You noticed it right away when he arrived. He said, ‘Man, this is great. This is tough competition, so you have to make your adjustments right away.’ And it will be good because wherever he goes next year, Double-A or Triple-A, he’s going to face that type of talent.”

Sims has the stuff and body frame to develop into a front-line starter. After some road bumps, the talented righty is starting to look like one in the AFL. 

Adam Brett Walker II, Minnesota Twins

AFL Stats: 16 G, .300/.400/.617, 5 HR, 17 RBI, 1.017 OPS

Is there a more exciting prospect in the minor leagues than Minnesota's Adam Brett Walker? 

The talented outfielder burst on the scene with a 25-homer season in High-A in 2014. Walker was promoted to Double-A in 2015, and proceeded to mash 31 homers and drive in 106 runs this past season. 

With his power, as in most cases, comes high strikeout totals. According to MLB.com, Walker's ability to curtail his swings-and-misses will dictate just how far he can progress:

"

Power, obviously, is what evaluators would call Walker's carrying tool. He has as much power potential as anyone in the Twins system not named Sano. He's also struck out in over 25 percent of his plate appearances as a pro, and therein lies the rub. How will Walker continue to tap into that prodigious raw power if he can't make enough contact? It remains to be seen, though he hit for power even with the move to Double-A in 2015.

"

Even with the K's, Walker has established himself has one of the most intriguing players in the minors. While in the AFL this season, he's continued to pad his resume with five homers and 17 RBI in 16 games. 

Power like Walker's doesn't grow on trees. He's displayed it at every level of the minors, including against top-notch pitchers in the AFL, which bodes well moving forward.

Gary Sanchez, New York Yankees

AFL Stats: 18 G, .299/.329/.649, 7 HR, 19 RBI, 4 SB, .979 OPS

Gary Sanchez has endured through a tumultuous minor league career with the New York Yankees, but it's hard to imagine his stock has ever been higher than it is right now.

Sanchez was given a $3 million signing bonus at the age of 16 and has found himself in the headlines for the wrong reasons on more than one occasion.

"Youthful mistakes and lack of maturity are expected for kids that get $3 million when they turn 16, but scouts are still regularly using expletives to describe Sanchez’s makeup," Kiley McDaniel of FanGraphs wrote. 

While those red flags are alarming, Sanchez enjoyed a productive 2015. The 22-year-old slashed .274/.330/.485 this past season, which includes a .295/.349/.500 slash line in 35 Triple-A Games.

Sanchez has carried that steady production into the AFL, where he leads the league with seven homers. He was the star of the AFL All-Star Game too, as he mashed a long homer as seen in the video above.

Brian McCann is the Yankees starting catcher, but Sanchez is in position to earn the backup role after the trade of John Ryan Murphy earlier this week.

"[Sanchez] had a really good year, made a lot of improvements," Girardi told Ryan Hatch of NJ.com. "Played extremely well in the fall league, off the charts, so I mean it's something that we're going to look at."

It has taken a while, but Sanchez seems like he's finally maturing into the powerful backstop the Yankees thought he would become. Because of that, his performance is the most eye-opening development from the AFL.

Stats courtesy of MLB and the Arizona Fall League and accurate as of Nov. 13.