The Mets also announced their starting pitcher for Monday night's series finale against Arizona. Right-hander Nelson Figueroa will be called up from Triple-A Buffalo to face Diamondbacks ace Dan Haren.
The 35-year-old Figueroa, who made one start for New York earlier this season, was 7-5 at Buffalo with a 2.25 ERA, second-best in the International League. He grew up rooting for the Mets in Brooklyn.
Figueroa was 3-3 with a 4.57 ERA in 16 games with the Mets last year, including six starts. To make room for him on the roster, New York optioned left-hander Pat Misch to Buffalo after Sunday's 5-2 loss.
The Mets needed a fill-in starter Monday because of a rainout last week and subsequent doubleheader.
The 40-year-old Sheffield had been sidelined since July 18 with a strained right hamstring. Signed just before Opening Day after getting cut by Detroit, he leads the Mets with 10 homers.
Sheffield nearly got a big hit off the bench Sunday. With a runner on third and one out in the fifth inning, he pinch hit for starting pitcher Mike Pelfrey and ripped a line drive to first that was caught by a leaping Chad Tracy, preserving Arizona's 3-2 lead.
"That was definitely a big swing," Mets manager Jerry Manuel said. "That was really probably the game, as to the shift in momentum or the way it was going."
Sheffield stayed in the game to play left field and was robbed again in the eighth on a diving grab by Diamondbacks left fielder Gerardo Parra.
Before the game, Manuel said there was a good chance Sheffield would start Monday.
"I like Gary in those night games," Manuel said. "He's still our leading home run hitter, so we've got to get him in there."
To make room for Sheffield on the roster, New York designated third-string catcher Robinson Cancel for assignment after Saturday night's 9-6 victory.
In other news, setup man J.J. Putz threw 20 fastballs and five splitters in his second bullpen session since June 9 surgery to remove a bone spur from the back of his right elbow.
"It went pretty well," Putz said. "No pain at all."
Putz said he wants to return sometime in August, hopefully in about three weeks.
Manuel watched the reliever throw and said he was very impressed and encouraged.
"He looked free and easy," the manager said.
Putz is slated for another bullpen session Wednesday, with an increased workload. He'll throw 20 pitches, then sit down for 3 minutes before getting up and tossing 10-15 more.
After that, Putz thinks the team will set up a schedule for him to face hitters and eventually begin a minor league rehab assignment.
"I think they've been pretty cautious with it. They're really going on how I feel," he said. "I think after Wednesday will be a big day to see how I feel after that."
Manuel also said he thought reliever Billy Wagner was scheduled for his second minor league rehab outing Monday. The left-hander has been out all season following elbow ligament replacement surgery.