James Jason Mecir (born May 16, 1970) is an American former baseball player.
He played for five teams in an 11-year career, and retired from the Florida Marlins in 2005.
He was a right-handed pitcher.
Mecir is notable for having overcome a birth defect (namely club feet) to become an effective Major League pitcher as well as for regularly throwing a screwball.
He spent 4½ years as a member of the Oakland Athletics and is prominently mentioned in Michael Lewis's bestselling book Moneyball: The Art of Winning an Unfair Game.