A Major League Baseball club has two rosters: the 25-man roster and the 40-man roster.
You’ve undoubtedly heard those terms countless times, but if you don’t actively think about what they mean, September affords an opportunity.
The 25-man roster is the active, big league roster. They’re the dudes in Chicago who can play in the Cubs’ games. The 40-man roster is that group, plus any player on the 15-day disabled list, and any player on an “optional assignment” to the minor leagues, who can otherwise be freely brought onto the 25-man roster if a need develops. The 40-man exists, among other reasons, because those players are on big league contracts that pay them at a much higher rate than the minor league base pay, and young players have to be placed on the 40-man roster after a certain period of service time in the minor leagues (which prevents teams from hoarding otherwise big-league-caliber players).
The reason this all matters right now is because, once we hit September 1, the possible “active” roster is no longer limited to just 25 players. From September 1 through the rest of the regular season, any player on the 40-man roster can be called up to play on the active roster. It’s a nice way to get exposure to the big leagues for younger players after the minor league seasons end, and it’s also a nice way for competitive teams to give their regulars a breather down the stretch. Sometimes, it’s also a way to bring up a specialized player – LOOGY, speed guy, glove guy, etc. – who might not otherwise have a spot on the 25-man roster.
There are considerations, though, beyond simply calling up every single player on the 40-man roster. First of all, for players not already on the 40-man roster, if you want to call them up, you’ve got to put them on there. And then, that player would have to stay on the 40-man roster all offseason, lest they be subjected to waivers. That’s why you almost never see a prospect who doesn’t have to be added to the 40-man roster before the Rule 5 Draft brought up in September. It eats up a 40-man spot all offseason, which is no good, because you want maximum flexibility at that time.
Further, there are playing time considerations, service time considerations, payroll considerations, and, yes, even physical space considerations.
Most teams call up an extra four to eight players for September, and I expect that to be the Cubs’ range, too, though they may be on the high end when you consider that many of their September roster additions won’t really be “call-ups” so much as “guys returning from injury.”
If everyone on the current 25-man roster sticks around come September 1, then you’ll also see the Cubs adding the following players within the first week of September: John Lackey, Hector Rondon, Pedro Strop, Joe Smith, Tommy La Stella, and Chris Coghlan.
Among the minor leaguers on the 40-man roster but not currently called up, you could see pitchers Pierce Johnson, Gerardo Concepcion, and Giovanni Soto. Other pitchers who could conceivably be added to the 40-man roster and brought up include Josh Collmenter, Joe Thatcher, Armando Rivero, Jose Rosario, and Jack Leathersich. Of note, guys like Rivero, Rosario, and Leathersich are due to be eligible for selection in the Rule 5 Draft in December unless they are put on the 40-man roster beforehand. Sometimes guys in that circumstance are slightly more likely to be called up in September, since they’ll eventually have to go on the 40-man anyway.
Position players you’ll see called up, in addition to La Stella and Coghlan, are Munenori Kawasaki and (probably) Jeimer Candelario, who has continued to quietly dominate at AAA. Albert Almora seems pretty likely to come back up, too, as he can get some valuable experience as the Cubs rest their regulars. I’m not sure we’ll see any non-40-man players added from there, though outfielders John Andreoli and Matt Murton have an outside shot, as does catcher Tim Federowicz, if the Cubs want a ton of depth there.
Although September is just two days away, we won’t necessarily see all the call-ups coming right away. First of all, the injured players (Lackey, Rondon, Strop, and Coghlan) are still in various stages of their recoveries, and will probably trickle back onto the roster in the first half of the month. Secondly, the Iowa Cubs season does not end until September 5, and many of the players will stay there before being considered for a call-up.