MLB September Call Ups, Roster Expansions and Playoff Rosters

September 1st is one of the final important dates for baseball fans for 2016's baseball calendar. The day signals the beginning of the roster-expansion period and at the same time it also marks the end of playoff eligibility for players. For those new to baseball this might be a contradiction.

September's roster-expansion period, sometimes called the "September call-up," refers to a period when the regular season ends in the minor leagues which in turn frees up additional players to join the big-league rosters.

Baseball teams are allowed to add as few players as they wish with the maximum roster possibly stretching from 25 to 40 players.

These additional roster spots are used by teams in varied ways. Some teams bring their rookies to give them exposure to the big-leagues. Other teams bring players who can provide depth, or who can take roles in situational baseball. Most teams mix-and-match between the strategies mentioned.

Occasionally some teams have an unbalanced number of players with one team possessing more players than their opponent. This issue is becoming more and more of a point of contention in the league.

Baseball officials apparently are going to enforce a 25-man limit rule during September which would demand teams to determine their active rosters before the games begin. However, the new rule has yet to be implemented.

In the past, to determine postseason eligibility a baseball player needed to be on the 25-man roster or on the disabled list when September 1 comes. However, this rule is no longer in effect because now all players on the 40-man roster are now eligible. Teams are allowed to pick their 25-man rosters before the playoff series.