An all-star team comprised of prospects, based on their performance in the minors during the month of August. Monthly all-prospect team archives available here.
The runs above average (RAA) estimates are calculated by Baseball America. For batters, weighted on-base average (wOBA) is used to calculate RAA, and for pitchers, runs allowed per nine innings (R/9) is used.
C Zack Collins • White Sox
High Class A Winston-Salem (Carolina)
Selected 10th overall in the 2016 draft out of Miami, Collins saved the best work of his full-season debut for August, when he led all minor league catchers with a 1.111 OPS. He earned his first promotion to Double-A Birmingham on Aug. 16 but spent more time in the Carolina League last month. Collins has been tested often behind the plate and has thrown out 39 percent of basestealers while catching 86 games (and counting).
1B Pete Alonso • Mets
High Class A St. Lucie (Florida State)
Big-time righthanded power is the calling card for Alonso, a 2016 second-rounder out of Florida. He led the Florida State League with 16 home runs when promoted to Double-A Binghamton on Aug. 24, and not even a hand injury that cost him roughly six weeks in April and May could slow his prodigious power pace.
2B Garrett Hampson • Rockies
High Class A Lancaster (California)
The 2016 third-rounder from Long Beach State ranks among the minor league leaders for hits (170) and stolen bases (51) in an outstanding full-season debut. The usual California League and Lancaster caveats apply, and to that point, Hampson has hit for very little power (.083 isolated slugging) in road games. But his on-base skills, speed and defensive versatility (10 games at shortstop in August) should serve him well.
3B Vladimir Guerrero Jr. • Blue Jays
High Class A Dunedin (Florida State)
Guerrero doesn’t turn 19 until spring training next year, yet he has displayed incredible mastery of the strike zone in his full-season debut. He leads the Florida State League with a .450 on-base percentage (while slugging .500) since his July 12 promotion from low Class A Lansing. Guerrero has a chance to lead the minors in OBP if he can edge Dunedin teammate Bo Bichette.
SS Kyle Holder • Yankees
High Class A Tampa (Florida State)
Holder drew five walks, hit two home runs and stole one base in August, meaning that in the absence of secondary contributions, his batting line was propped up by a .468 average on balls in play. While that performance could very well be a BA-blip, the 2015 first-rounder from San Diego has such a fantastic defensive reputation that he wouldn’t have to hit that much to serve as a new-age John McDonald or Brendan Ryan.
OF Eloy Jimenez • White Sox
Double-A Birmingham (Southern)
The prize prospect acquired from the Cubs in the Jose Quintana trade, Jimenez decimated the high Class A Carolina League—hitting .302 with a .268 isolated slugging—prior to his Aug. 16 promotion to Double-A Birmingham. A right shoulder injury cost him about six weeks at the beginning the season, but Jimenez made necessary improvements to his home-run output and walk rate when he returned.
OF Brent Rooker • Twins
High Class A Fort Myers (Florida State)
The College Player of the Year runner-up at Mississippi State this spring, Rooker fell to the Twins in the supplemental first round and has mashed his way to high Class A in his pro debut. The righthanded slugger had clubbed 18 home runs through 60 games (he spent about a month at Rookie-level Elizabethton), evoking the power exploits of Evan Longoria (18 homers in 2006) or Joey Gallo (22 in 2012) in their pro debuts.
OF Justin Williams • Rays
Double-A Montgomery (Southern)
The 22-year-old, lefthanded-hitting corner outfielder began to access his power more frequently after the Southern League all-star break. He slugged .529 with 11 home runs through 56 games in the second half, a performance that included nearly as many walks (31) as strikeouts (34) and a three-homer game on Aug. 30.
RHP Rogelio Armenteros • Astros
Triple-A Fresno (Pacific Coast)
The crafty 23-year-old Cuban righthander has thrived at Double-A Corpus Christi and Triple-A Fresno this season by virtue of a sneaky fastball and four other pitch types. Armenteros’ 2.04 ERA ranks him squarely in the top 10 for qualified minor league starters.
RHP Shane Bieber • Indians
Double-A Akron (Eastern)
The 2016 fourth-rounder from UC Santa Barbara had walked 10 batters through 27 starts, which was good for a walk rate of 0.5 per nine innings, the best in the minors. Bieber doesn’t have huge stuff—he throws three potentially average pitches—but his plus control and success at three minor league levels this season, including 157 strikeouts in 167.1 innings, is difficult to ignore.
RHP Jon Duplantier • Diamondbacks
High Class A Visalia (California)
Not even a promotion to the hitter-friendly California League could slow Duplantier, a 2016 third-rounder out of Rice. His walk rate ticked up against better hitters, but he continued to miss bats and avoid home runs. Duplantier carried a 1.37 ERA into his final start, all but assuring him of ranking inside the top 10 for minor league starters since 1993. Justin Verlander’s 1.29 ERA is out of reach, but No. 2 is a distinct possibility.
RHP Jack Flaherty • Cardinals
Triple-A Memphis (Pacific Coast)
Flaherty turned in one of the great prospect breakthrough seasons, recording a 2.18 ERA in 25 starts at Double-A Springfield and Triple-A Memphis that ranks among the top 15 in the minors. He also struck out 147 in 148.2 innings prior to his big league callup, thanks to enhanced velocity—he sat 94 mph in the majors—which had been projected for 2014 first-rounder out of high schooler.
LHP Austin Gomber • Cardinals
Double-A Springfield (Texas)
Gomber has recorded a career 2.85 ERA in 452 pro innings while moving one level per year since the Cardinals made him a 2014 fourth-rounder from Florida Atlantic. After a big August, the 23-year-old southpaw ranks among the Texas League leaders for ERA (3.34), strikeouts (140) and opponent average (.219) thanks to his feel for sequencing a three-pitch mix.