September means expanded rosters: Here's what you should know

August 31st, 2023

Reinforcements are on the way!

When the calendar flips to Sept. 1 on Friday, all 30 teams can expand their rosters, calling on help from the farm. It’s not quite the same as it used to be, when scores of Minor Leaguers might get the chance to impact a playoff race or audition for a full-time spot for the following season. But there can be impact nonetheless.

Here’s what you need to know ahead of roster expansion on Friday:

Roster limits
Teams have been at the new normal 26-man levels all season. Come Sept. 1, through the rest of the season, active rosters will expand again to cover 28 players, no more, no less. Teams can carry 14 pitchers at most, too, to cut down on the endless parade of bullpen arms that often made September games a slog.

The hard cap at 28 is an important distinction from Septembers of old. Previously, clubs could call up any member of the 40-man roster for the month. That is no longer the case, though even a boost of two extra players should be helpful for the stretch run.

Minor League schedule
The Single-A and High-A regular seasons will end on Sept. 10, Double-A concludes a week later on Sept. 17 and the Triple-A season extends all the way to Sept. 24. There won’t be as much a concern that any farmhands close to the Majors aren’t fresh or in game shape throughout the month ahead.

Rookie eligibility
One of the other changes from previous years is that any service time, at-bats or innings pitched accrued in September do count toward rookie eligibility. In other words, there will be prospect graduations coming in the weeks ahead.

That said, any prospect called up at this point -- such as or -- is unlikely to hit the 45-day requirement to lose rookie status. (They could still reach 130 at-bats or 50 innings pitched, but that is also improbable.) So even if we see an onslaught of prospect promotions shortly, then don’t expect the callups to take players out of the running for 2023 Rookie of the Year Awards. That brings us to the next point …

Effect of new CBA
The most recent collective bargaining agreement signed by MLB and the MLBPA instituted a new policy starting in 2022 aimed at curbing service-time manipulation. A club that starts a top prospect on its Opening Day roster while he retains rookie status is eligible to receive an extra Draft pick if the player gets sufficient award consideration before he becomes arbitration-eligible. It’s part of the reason why we saw big names like Julio Rodríguez, Bobby Witt Jr. and Spencer Torkelson make Major League rosters out of the gate back at the start of 2022, and with Rodríguez’s Rookie of the Year win giving the Mariners an extra pick in this year’s Draft, there’s already been a strong early return to encourage other teams to follow suit.

This is all interesting, but how does it impact this September?

Well if clubs are considering starting their top prospects out of the gate next year, they might be more likely to give them their debuts now, in order to experience the Majors for the first time and make whatever adjustments necessary in the offseason to hit the ground running in late March.

Buckle up. Domínguez and Mauricio may have just been the start. We could see an onrush of more prospects over the next month.

Top prospects who could get the call

There are a number of players on our Top 100 list who could get the call to help out down the stretch. Some could get the chance to bolster a postseason run and some could be called up to teams out of the race to help them hit the ground running in 2024. Here’s a list of prospects in the top 50 to check the transaction wire for in the coming days, with their rank in parentheses):

, SS, D-backs (No. 10)
, OF, Cubs (No. 12)
, OF, Orioles (No. 14)
, SS/3B, Twins (No. 18)
, OF, Orioles (No. 25)
, 3B/2B, Tigers (No. 26)
, SS, Giants (No. 27)
, 3B/2B, Rays (No. 36)
, C/1B, A’s (No. 48)