MLB September Call-Ups Rule Explained

September baseball is just around the corner, and that means rosters are set to expand as teams prepare for the playoff push.

And though you may have heard some rumors about the amount of expansion changing, that's not really taking place until 2020.

Plenty of new faces are about to make their way to major league stadiums, but with the rules set to change soon, it's pertinent to go over what MLB teams can do.

MLB September Call-Ups Rule

As has been the case in the past, roster sizes will expanded from 25 men to 40 at the start of September. Any player on the 40-man roster can be called upon to play for the major league club.

That rule is set to change in 2020, though. Starting next year, the roster size will only expand to 28, up from the Opening Day number of...26. In this new instance, teams will be required to carry 28 players. The change is meant to put an end to the vast discrepancies in roster size that frequently cropped up during Septembers past.

Teams that were in the playoff push would take full advantage of the expanded rosters in order to rest players, whereas other teams would stay at or near the usual 25 men. On occasion, you'd see lengthy games packed with time-wasting pitching changes. Not entirely pretty.

There are still concerns that the 28-man roster for 2020 and beyond will lead to more service time abuse, which has been a major problem for young players over the past few years.

Time will tell if those concerns turn out to be well-founded.