Minor League Roster Rules

1. An MLB club can automatically renew a minor league player's contract no more than six times, so a club can unilaterally control a minor league player (that is, a player not on an MLB 40-man roster) for no more than seven minor league seasons. A player accrues a minor league season if he spends all or any part of a season on a minor league club's active list and/or disabled list (including all or parts of any season spent on Optional Assignment to the minors, but not including any season where the only time spent in the minor leagues was a minor league injury rehab assignment). 

2. A free-agent with prior MLB and/or minor league service who signs a minor league contract must be added to a minor league Reserve List within 15 days, and is not eligible to play in a game until he is added to his minor league team's Reserve List and Active List.

3. A player who has not previously signed an MLB or minor league contract can be "Signed for Future Service" (contract is for the following season) if the player signs a minor league contract after July 1st and is not placed on a minor league club's Active List prior to the conclusion of the Minor League season. (Attendance at a post-season Instructional League and/or participation in Instructional League games do not count). A player who is "Signed for Future Service" does not count against a minor league club's Active List or Reserve List until Opening Day of the following season. A player who is "Signed for Future Service" cannot be released until he receives a 15-day trial in Spring Training

4. A player who was eligible for selection in the First-Year Player Draft (MLB Rule 4 Draft) who signs a minor league contract after being selected in the previous Rule 4 Draft or as a Non-Drafted Free-Agent (NDFA) and who is not "Signed for Future Service" must be added to a minor league club's Active List within 15 days or when he plays in his first game (whichever comes first), but the player does not count against the minor league club's Reserve List until MLB and Minor League reserve lists are filed in November. The player cannot be released until he spends at least 15 days on a minor league active list.

5. A position player making a position change to pitcher or a pitcher making a position change to position player receives a one-year exemption from minor league service time restrictions. NOTE: A position player being converted to a pitcher may not be used as a position player in a minor league game during the exempt year, and a pitcher being converted to a position player may not be used as a pitcher in a minor league game during the exempt year.

6. A player on a minor league injury "rehab" assignment does not count against the minor league club's Reserve List or Active List, or the minor league club's service time restrictions.