The Mets made the moves before Friday night's game against Atlanta. They also scratched left fielder Jason Bay from the starting lineup because of a jammed right shoulder.
Hairston's move was retroactive to Aug. 24, a day after he strained his left oblique while taking a swing.
The 40-year-old Batista began the season with St. Louis and was 3-2 with a 4.60 ERA in 26 games, including one start. He joined the Mets in July and went 3-0 with a 4.24 ERA at Buffalo.
Batista is set to pitch for his 10th team in the majors. The Mets need a spot starter next week and may use Batista.
