Two-way Players
Definition
MLB teams, in general, must designate every player on the active roster either as a pitcher or a position player, and are limited to carrying 13 pitchers on the active roster (14 pitchers from Sept. 1 through the end of the regular season).
Players who are designated as position players are not allowed to pitch unless the game is in extra innings or their team is ahead or trailing by more than six runs when they take the mound.
However, teams can also designate players as two-way players -- players who are both position players and pitchers -- if they meet certain criteria. Two-way players are able to pitch in any situation but don't count toward the active roster's pitcher total.
Players qualify for the two-way player designation if they have met both of the following conditions in either the current MLB season or any of the two previous seasons:
• Pitched at least 20 Major League innings
• Started at least 20 Major League games as a position player or designated hitter, with at least three plate appearances in each of those games