Future Shock: Chapman’s Time is Now

September means roster expansion; this typically equates to "more arms"—and every year, a handful of players prove enough to stick around come October (remember Francisco Rodriguez in the 2002 playoffs?). Here are 10 potential September call-ups—all associated with contenders—who could stick around into the postseason.

Jonathan Albaladejo, RHP, New York Yankees (Triple-A Scranton/Wilkes Barre)
The 27-year-old Puerto Rico native has a career ERA of 4.80 in 41 appearances for the Yankees over the past three seasons. Not good, right? That pitcher, though, is a very different player than the current incarnation. Albaladejo has all but scrapped his sinker in favor of a pure four-seam heater that sits at 92-94 mph while touching 96. He's been one of the best relievers in the minors this year; he's already established an International League record with 40 saves to go with a 1.35 ERA while striking out 76 over just 60 innings. He won't be on the playoff roster, but September could be a springboard to a more realistic shot at a job next spring.

Aroldis Chapman, LHP, Cincinnati Reds (Triple-A Louisville)
Of all the relievers still in the minors, Chapman is the most likely to pitch in high-leverage playoff situations, provided the Reds reach the postseason. Since moving to the bullpen in late June, the 22-year-old high-profile Cuban signee has been nothing short of a force of nature. He has consistently hit triple digits with his fastball while putting up a 0.96 ERA since the All-Star break with 30 strikeouts in 18 2/3 innings. He arguably has better stuff than any southpaw in the big leagues, and could address one of Cincinnati's few weaknesses.

Rafael Cova, RHP, San Francisco Giants (Double-A Richmond)
Cova, a strong-armed righty who has bounced around three organizations and had a pair of stints in Mexico, is already 28. That's a bit damning, but he's having a good year—he's been touching 97-98 mph with a fastball that normally sits in the mid 90s. His command and control remain an issue, but at the same time, he's allowed just 25 hits in 49 1/3 innings while striking out 56. He's a late bloomer for sure, but also close to being rewarded for his persistence.

Craig Kimbrel, RHP, Atlanta Braves (Triple-A Gwinnett)
With two plus-plus pitches (fastball and slider), Kimbrel has the ability to dominate big-league hitters, and he's already proven it with 15 strikeouts in just 8 2/3 innings during a pair of looks with the Braves. Unfortunately, his inability to throw strikes (10 walks) has left Bobby Cox lacking in confidence when it comes to the thickly built right-hander. While Kimbrel will be relegated to mop-up work down the stretch, he simply needs the experience. He could replace Billy Wagner as closer in Atlanta.

Scott Mathieson, RHP, Philadelphia Phillies (Triple-A Lehigh Valley)
Mathieson is 26 and in his eighth professional season—but he hardly has the stuff of someone with such a résumé. His fastball can get into the upper 90s and he adds in an average slider to keep hitters honest. With a 2.62 ERA and 78 strikeouts in 58 1/3 innings for Lehigh Valley, he's been especially dominant of late, including 13 whiffs over his past seven innings. Mathieson could, at the very least, supply a bit of stability to a consistently inconsistent bullpen.

Jake McGee, LHP, Tampa Bay Rays (Triple-A Durham)
McGee is an extremely hard-throwing lefty. After 2008 Tommy John surgery, he struggled with control. So far this year, he's looked more than ready, recording 16 strikeouts over 9 1/3 innings while giving up four hits and walking one. McGee's mid-90s heat is rare in a southpaw. He could be pitching for the Rays in October.

Scott Munter, RHP, San Diego Padres (Triple-A Portland)
The Padres don't exactly need help in their 'pen right now, but Munter should at least provide some innings come September. The former Giant was hampered by an inability to miss bats in the majors, but he's recorded 57 Ks over 64 innings in the Pacific Coast League this year. While his outstanding sinker remains the bread and butter of his game, the 30-year-old veteran's ability to suddenly get some strikeouts might be the beginning of a return to big-league middle relief.

Eduardo Sanchez, RHP, St. Louis Cardinals (Triple-A Memphis)
Sanchez is more of a 2011 play, but he'll likely get a September look in order to keep the existing bullpen arms fresh for the postseason. Under 6 feet tall and skinny as a rail, Sanchez shocks scouts by getting mid-90s heat out of his lightning-fast arm action, while adding a bit of natural sink and an impressive slider.

Tanner Scheppers, RHP, Texas Rangers (Triple-A Oklahoma)
Scheppers might be the only bad decision the Rangers have made this year. They moved him from the 'pen to the starting rotation to give him more innings in the minors. He wasn't cut out for starting—he had to use a generally subpar changeup too much and was battered around for a .330 batting average while putting up a 5.84 ERA in the Oklahoma rotation. Now he's back in the 'pen and his numbers aren't great there, either. He should get a call-up, but how significantly he impacts the Rangers across the next two months is in question.

Anthony Slama, RHP, Minnesota Twins
Slama got called up to Minnesota over the weekend. While Slama's career minor-league mark of 12.6 strikeouts per nine innings makes him look like a fireballer, he's anything but. His fastball is only a tick above average, while his slider is no more than solid average. His game revolves far more around location and deception than pure stuff, but scouts think he's a good enough magician to fool big-league hitters.

A version of this story originally appeared on ESPN Insider .