The time has come for MLB teams to pad out their rosters with September call-ups, although this year's round of roster additions will be significantly smaller.

Unlike in years past when rosters expanded to 40 players for the season's final month, active rosters will only move up from 26 to 28 players this September. That likely means fewer opportunities for unproven prospects to get their feet wet on contending teams, as those teams will prioritize immediate contributions.

Players who are already on the 40-man roster are also more likely candidates to be called up, as no corresponding roster move is required to bump them up to the majors.

With all of that in mind, we've highlighted 10 potential September call-ups primed to impact pennant races. Even if these guys don't immediately join their team's active roster on Sept. 1, expect them to contribute at some point in the coming month.


SS Jose Barrero, Cincinnati Reds

Shortstop has been a constant question mark for the Cincinnati Reds since Zack Cozart left town.

It looked like an answer had emerged when slick-fielding Kyle Farmer hit .446/.500/.750 with 10 extra-base hits in 14 games coming out of the All-Star break to close out July.

However, his offensive production has leveled off in August. The 31-year-old is hitting .240/.260/.370 in 104 plate appearances, which could open the door for top prospect Jose Barrero to get another look in September.

One of baseball's top middle infield prospects, Barrero hit .292/.358/.625 with four doubles and four home runs in 12 games at Triple-A to start the month of August before earning his first big league action of the 2021 season. He went 2-for-12 with four strikeouts in six games before he returned to the minors on Aug. 28 following the addition of veteran Asdrubal Cabrera, but he likely won't be back down for long.

All told, Barrero is hitting .303/.378/.532 with 19 doubles, 17 home runs and 62 RBI in 80 games between Double-A and Triple-A, and he is the shortstop of the future in Cincinnati.


OF Skye Bolt, Oakland Athletics

With Ramon Laureano suspended, Stephen Piscotty out for the season following wrist surgery and Seth Brown sidelined after a positive COVID-19 test, the Oakland Athletics are in need of outfield help.

Utility players Josh Harrison, Tony Kemp and Chad Pinder are all capable of manning an outfield spot, but it would make sense to use September roster expansion to add more depth in that area.

Skye Bolt has earned his shot.

The San Francisco Giants claimed Bolt off waivers in April, but he returned to Oakland a month later. He has spent the bulk of the season at Triple-A Las Vegas, where he's hitting .387/.492/.650 with 23 extra-base hits in 199 plate appearances.

The 27-year-old hit only .105/.121/.193 in 60 career plate appearances at the MLB level over the past two seasons, but he has been raking all year in the minors.

It's worth seeing if he can provide a spark to the lineup as the A's battle for a wild-card berth.