The Temporarily Inactive List is essentially an in-season excused Leave of Absence, and it is used for Paternity Leave, Bereavement Leave, and Family Medical Emergency Leave, as well as when a player is delayed reporting to a new club, or is attending college, or is incarcerated, or has returned home for personal reasons. Only minor league players (including players on Optional Assignment to the minors) can be placed on this list.
A player on the Temporarily Inactive List does not count against his club's Active List, but he does count against the club's Reserve List. (If a minor league club's Reserve List is full, a player who ordinarily would have been placed on the Temporarily Inactive List can be placed on the Restricted List instead, but placing a player on the Restricted List does require the approval of the MLB Commissioner).
A player cannot be placed on the Temporarily Inactive List any earlier than the start of his club's regular season, the player must remain on the Temporarily Inactive List for at least three days, and a player on the Temporarily Inactive List must be reinstated no later than the conclusion of his club's season.
A player normally is not paid while on the Temporarily Inactive List (club option).