Murphy got the shot during Tuesday's trip to the Hospital for Special Surgery, according to a major league source.
Manager Terry Collins said Murphy is being cautious after third baseman David Wright and outfielder Scott Hairston experienced side-muscle issues last spring training in Mets camp. Hairston's injury lingered throughout spring training, but both made it back for the Opening Day roster in 2012.
"I think we want to be proactive and get me up to New York, especially with all the success they had with David and Scotty last year," Murphy said. "This seems to be the best course of action. The best-case scenario would be take a couple of days off and it'll be fine. But from everyone I talked to, the shot is not a bad thing. It's a good solution to the problem. But I can't say what's going to happen. I just know we'll go up there and get it checked out by the doctors.
"... Unfortunately it's something that happened. But for it to happen early, I think we'll be able to get this out of the way. I don't foresee it being a problem after the next week to 10 days."
Murphy said he was able to play through similar discomfort late last season. He suggested the resurfacing of the issue might be the result of subtle changes to his stance during spring training.
"An encouraging part for me is I was able to play through it last year," Murphy said. "If I needed to play, if we had a game, I would play. But I think that right now, as an organization, they just want to play it smart. It's better to miss the first week of spring training than the first week of the season."
Murphy went through most of the first full-squad workout Monday, but was not permitted to swing a bat. He said one of his bigger concerns is going in an MRI booth, "because I don't like those things very much."