Putting Top September Call-Up Candidates Through the B/R Combine

While countless big-name prospects already have been promoted to the major leagues this season, and more appear poised to debut before the end of the month, the greatest influx of young talent is yet to come.

On September 1, the active roster will expand from 25 to 40 players, meaning that a majority of the players on the 40-man roster will get a crack at the major leagues during the final month of the season. Additionally, some teams see it as a chance to promote a prospect from outside the 40-man roster, although it comes at the expense of a corresponding roster move.

While it’s still hard to say with any sense of certainty which prospects will get the call this September, there certainly are some intriguing candidates.

So, in anticipation of the final wave of promotions this season, here’s an in-depth look at the best tools and pitches among this year’s potential September call-ups.

Best Hitter: Oscar Taveras, OF, St. Louis Cardinals

Even though a lingering ankle injury has limited Oscar Taveras to only 46 games this season, he still ranks as the best pure hitter in the minor leagues. The 21-year-old possesses preternatural bat-to-ball skills that, when combined with the extension achieved after contact, give him the ability to drive any pitch from line to line.

Update (8:08 p.m. ET): According to Jenifer Langosch on Twitter, Taveras will undergo season-ending surgery next week to repair a high right ankle sprain. Therefore, the honor will now go to Xander Bogaerts.

Best Bat Speed: Xander Bogaerts, SS-3B, Boston Red Sox

While Bogaerts has always possessed plus bat speed, he’s taken it to a new level over the last year as he’s added strength and tightened his approach. What I like most about the 20-year-old’s bat speed is how he still shows effortless barrel control through the zone and smokes tough pitches to all fields.

If he wanted to, Bogaerts could easily sell out for more power—easily. But he doesn’t. He stays short and quick to the ball while utilizing his tremendous plate coverage.

Best Strike Zone Judgment: Kolten Wong, 2B, St. Louis Cardinals

Kolten Wong is one of the more polished hitters in the minor leagues—as he was expected to be when the St. Louis Cardinals selected him in the first round of the 2010 draft. As a top-of-the-order hitter—an ideal No. 2 hitter—Wong demonstrates excellent pitch recognition that in turn fuels his high contact rate.

He doesn’t strikeout or walk much; just a lot of deep counts and hard contact.

Best Power: George Springer, OF, Houston Astros

At 6’3”, 200 pounds, George Springer’s combination of strength and athleticism has made him one of the more consistent sluggers in the minor leagues over the past two seasons, not to mention the first player to turn in a 30-30 season since prospect-turned-priest Grant Desme accomplished the feat in 2009.

For Springer, showcasing plus power comes as naturally as striking out—though, in his defense, the approach has been better this season. He has a swing that involves a slight front-side leak toward the plate and occasional hard landing. For that reason he may be susceptible to a tough adjustment period upon reaching the major leagues, but the potential is there for multiple 25- to 30-home run seasons in his prime.

Best Speed: Billy Hamilton, OF, Cincinnati Reds

Billy Hamilton is the fastest player I’ve ever seen and unsurprisingly owns the best home-to-first time I’ve ever recorded (3.47 seconds on a left-handed bunt in the 2012 AFL Rising Stars Game). Additionally, he has the ability to put enormous pressure on opposing defenses, as his feet literally never stop moving on the field.

The 22-year-old set a professional record last season by swiping 155 bases in 132 games between High-A Bakersfield and Double-A Pensacola. Although his total this season is nothing close to last year’s, Hamilton has actually been more efficient on the basepaths with an 84.1 percent success rate (69 for 82).

The only difference is that the improved contact and on-base skills that he showed last year have not translated this season at Triple-A Louisville.

Best Baserunner: Jackie Bradley, OF, Boston Red Sox

Although Jackie Bradley is technically only an above-average runner, his speed on the basepaths plays up thanks to a high baseball IQ and superb instincts. He takes aggressive leads and picks his spots to steal bases, and he takes an extra base as well as any player in the minor leagues.

Best Defense Infielder: Chris Owings, SS, Arizona Diamondbacks

One of the better defensive shortstops in the minor leagues, Chris Owings is an instinctual defender with quick feet and showcases excellent body control in all directions. In general, he shows smooth, fluid actions to the ball and consistently works around it so as to generate momentum toward the target.

Best Defensive Outfielder: Jackie Bradley, Boston Red Sox

Although he stands out for his plate discipline and on-base skills, Bradley’s greatest strength is his defense in center field.

The 23-year-old makes it look easy out there with above-average speed and tremendous instincts that result in plus range. He gets excellent jumps and consistently takes a direct route to the ball while showcasing closing speed in all directions.

Best Infield Arm: Xander Bogaerts, SS-3B, Boston Red Sox

Scouts are divided about his ability to remain at shortstop long term, but there’s no question that Bogaerts has the necessary plus arm strength for the left side of the infield. While he’s always been able to get the ball out of the glove and throw darts across the infield, the 20-year-old improved body control and has also improved his overall accuracy.

Best Outfield Arm: George Springer, Houston Astros

Springer's plus arm is suitable for all three outfield positions, even right field. But as a center fielder, it’s an underrated weapon that could rank among the best in the game when he reaches the major leagues. The 23-year-old also gets outstanding carry on his throws thanks to a long arm on the backside, high release point and aggressive follow-through.

Best Defensive Catcher: Christian Bethancourt, Atlanta Braves

A physically strong and athletic catcher at 6’2”, 215 pounds, Christian Bethancourt has the best arm strength among minor league backstops—a legit, 80-grade, rocket. His catch-and-throw skills have continued to improve with experience, resulting resulted in consistent sub-1.8-second pop times and 37 percent career caught-stealing rate.

The 21-year-old’s blocking and receiving skills have progressed over past two seasons, though another half-season or so of refinement in the minor leagues wouldn’t hurt.

Best Fastball: Yordano Ventura, RHP, Kansas City Royals

In spring training, there were reports of Yordano Ventura’s fastball reaching 102 mph, which isn’t surprising considering he’s tacked on nearly 40 pounds to his 5’11” frame since the beginning of the 2012 season.

The velocity comes effortlessly for the 22-year-old right-hander, as Ventura’s long arms and extension toward the plate make his fastball play even hotter and jump on opposing hitters. And compared to many of the other pitching prospects who flirt with triple digits, Ventura stands out for his ability to sustain the velocity deep into starts.

Best Curveball: Archie Bradley, RHP, Arizona Diamondbacks

Owner of the best fastball-curveball combination in the minor leagues, Archie Bradley’s curveball is an absolute hammer (70-grade pitch) thrown with velocity and tight spin. Because the 21-year-old works on a steep downhill plane toward the plate, the pitch has a devastating, 12-to-6 shape that generates excessive whiffs.

The right-hander’s feel for the pitch has improved considerably this season, as he now demonstrates the comfort and confidence to throw it in any count.    

Best Slider: Erik Johnson, RHP, Chicago White Sox

One of the few bright spots in the Chicago White Sox’s barren system, Erik Johnson is a 6’3”, 235-pound right-hander with a projectable four-pitch mix. The 23-year-old also possesses my favorite slider of all pitching prospects with the potential to reach the major leagues this September.

Working off a fastball plane, Johnson creates excellent depth and tilt on the pitch. Meanwhile, his ability to both throw the pitch for a strike and bury it in the dirt has vastly improved over the course of the 2013 season.

Best Changeup: Kevin Gausman, RHP, Baltimore Orioles

After taking a long look at Kevin Gausman this season between spring training, Double- and Triple-A, and the major leagues, I’m convinced that the right-hander’s plus-plus changeup is the best among all pitching prospects.

With anywhere from a 12 to 15 mph speed differential relative to his fastball, Gausman throws the offering with convincing arm speed, while his arm action creates additional deception and makes it difficult for the hitter to recognize out of the hand. And as his fastball command continues to improve with experience, the pitch should become an even greater weapon.

Best Control: Kevin Gausman, RHP, Baltimore Orioles

As I alluded to in the above write-up, Gausman’s tendency to work up in the zone with his mid-to-upper-90s fastball—an approach that is typically effective against minor league hitters—was exploited this season upon reaching the major leagues (seven home runs in 33.1 innings), as he quickly learned that hitters in The Show have no issues with turning around velocity.

That being said, it’s not as though Gausman has been one to issue free passes during his brief professional career. In fact, the 22-year-old has only walked 24 batters in 122.1 innings (1.8 BB/9) since turning pro.

Besides his ability to pound the strike zone with his fastball, Gausman’s feel for his changeup allows him to command the pitch with ease. And even though the right-hander’s breaking ball is both his least developed and used offering, he manages to keep it around the plate and induce weak contact.

Best Reliever: Vic Black, RHP, Pittsburgh Pirates

The No. 49 overall selection in the 2009 draft, Vic Black quickly flamed out as a starter due to his inability to stay on the field. Finally healthy for the 2012 season, the 6’4” right-hander had a breakout campaign with Double-A Altoona in his first stint as a full-time reliever.

The 25-year-old has built upon his success this season at Triple-A Indianapolis, showing vastly improved command of his upper 90s fastball and wipeout slider. Overall, he’s registered a 2.16 ERA and 59-17 strikeout-to-walk ratio with 16 saves in 41.2 innings. Black also received his first taste of the major leagues this season, making three appearances out of the Pittsburgh Pirates’ bullpen following the injury to closer to Jason Grilli.

While he lacks a clear path to the ninth inning due to the presence of both Grilli and Mark Melancon, Black, who’s already on the team’s 40-man roster, should be back in the major leagues in the near future.