The team also activated backup catcher Tomas Nido and called up several players from the minors as major league rosters expanded Sunday. Nido had been on the seven-day injured list with a concussion.
Nimmo drew a pinch-hit walk in the eighth inning Sunday night against Philadelphia and came around to score the tying run on a wild pitch. New York lost 5-2 to the Phillies.
Nimmo had been sidelined since May 21 and just completed a minor league rehab assignment at Triple-A Syracuse. He was hitting .200 with three homers and 14 RBI for the Mets this season.