With active rosters set to expand from 25 to 40 on Tuesday, more blue-chip prospects will come up for the season's final month. Some already have appeared in the Majors earlier this year, while others will be making their debuts. Here are 10 of the best prospects we're likely to see in September:
Corey Seager, SS/3B, Dodgers (No. 2 on MLBPipeline.com's Top 100 Prospects list)
Los Angeles doesn't have to protect him on its 40-man roster until after the 2016 season, so it's not a given that Seager will get a look in September. But the best prospect currently in the Minors would be an upgrade over Jimmy Rollins at shortstop and the slumping Justin Turner at third base.
Joey Gallo, 3B/OF, Rangers (No. 6)
Gallo slammed five home runs for Texas in June, including one off Clayton Kershaw, but he also struck in 44 percent of his plate appearances and provided erratic defense at third base. He has continued to pile up homers and strikeouts at Triple-A Round Rock while getting more time in left field, where the Rangers could use some help.
Aaron Judge, OF, Yankees (No. 19)
In July, when New York was scoring runs in bunches and he was scuffling at Triple-A Scranton/Wilkes-Barre, Judge figured to wait until next year to make his big league debut. Now the Yanks are struggling and he's rediscovered his power stroke, so they could turn to him for help just like they did with Greg Bird two weeks ago.
Jose Berrios, RHP, Twins (No. 23)
Like Seager and Judge, Berrios won't require a 40-man roster spot until after the 2016 season. Nevertheless, Minnesota is fighting for its life in the American League Wild Card race, and its starters have posted a 5.88 ERA in August. He has better stuff than anyone in the Twins' rotation and is on a roll, with seven quality starts in his past eight outings for Triple-A Rochester.
Jose Peraza, 2B/OF, Dodgers (No. 27)
After trading for him in July, Los Angeles promoted Peraza in August when Howie Kendrick went on the disabled list, then sent him down after dealing for Chase Utley. Peraza almost certainly will return when rosters expand, and his well-above-average speed could earn him a postseason role as a pinch-runner.
Archie Bradley, RHP, D-backs (No. 42)
Arguably baseball's best pitching prospect a year ago, what was supposed to be Bradley's first full season in the Majors has been marred by a line drive to the face in April and shoulder inflammation that landed him on the disabled list in June. After a couple of more rehab starts, he should resurface in Chase Field.
Blake Snell, LHP, Rays (No. 45)
No Minor League pitcher has had a better season than Snell (13-4, 1.31 ERA, 151 strikeouts in 124 innings, .175 opponents average). He already has pitched a career-high 124 innings, but Tampa Bay is still in the AL Wild Card hunt and could use another quality lefty in its bullpen after Jake McGee went down with a knee injury.
Dalton Pompey, OF, Blue Jays (No. 48)
Pompey opened the season as Toronto's center fielder, but he lost the job to Kevin Pillar after hitting .193/.264/.337 in April. He didn't find his mojo until a pair of demotions, but he has been raking for the past three months while Pillar's bat has cooled. They're both quality defenders and Pompey has a higher offensive ceiling, so he can help the Blue Jays' postseason chances.
Frankie Montas, RHP, White Sox (No. 59)
Montas actually joined Chicago as the 26th man for a July 17 doubleheader against the Royals, though he went back to Double-A Birmingham the next day and has yet to appear in a big league game. That should change shortly, as he should get a chance to audition for a 2016 rotation spot. The hardest thrower among all the pitchers on this list, Montas hit 101 mph during the SiriusXM All-Star Futures Game.
Carl Edwards Jr., RHP, Cubs (No. 62)
Chicago is for real, Edwards already is on the 40-man roster and he could offer some bullpen depth. He can get swings and misses with both his fastball and curveball, though his control has been shaky since he has transition to relief, which will preclude using him in high-leverage situations.
Jim Callis is a reporter for MLB.com and writes a blog, Callis' Corner. Follow @jimcallisMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.