Wagner experienced tightness in his left shoulder on Sunday afternoon in Cincinnati as he warmed up in the bullpen before striking out the side in the 10th inning to secure the Mets' 7-5 victory.
He said afterwards that he had been bothered of late by discomfort in his left trapezius muscle. The tightness he experienced on Sunday was in an adjacent area of his left shoulder. Wagner said the discomfort felt like a cramp, and suggested that a nerve might be impinged. His general diagnosis was: "My shoulder's a little tight."
He didn't anticipate having an MRI at that point.
Wagner said the trapezius has bothered him for about two weeks.
"I'm old [he turns 37 Friday]; I'm supposed to hurt," he said.
The Mets were concerned enough about the tightness that manager Jerry Manuel and trainer Ray Ramirez visited Wagner on the mound during the at-bat of Paul Bako, the first batter Wagner faced Sunday.
Wagner said he had experienced similar problems in the past, and solved them by "going out and pitching." He threw 16 pitches, 10 for strikes, Sunday to earn his 24th save in 30 opportunities. He had pitched one inning Thursday night after pitching one in the All-Star Game on Tuesday.
"It seems fine now," he said afterward. "It wasn't that bad. When Jerry came out, I thought it was for someone else. ... It doesn't seem bad. If it is, I'll miss the first game [of the Phillies series], and if we're winning by more than three, that won't matter."
Marty Noble is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.