DeGrom said before the game at St. Louis on Saturday that his elbow soreness likely was from altering his routine during a recent bout of strep throat.
"After getting some treatment and getting things moving around, it started feeling a little better," deGrom said. "So decided to throw and felt good with how it went."
The Mets placed deGrom on the injured list Friday retroactive to April 16 because of right elbow soreness. The club had announced that deGrom would be returning to New York for an MRI of his elbow.
Mets manager Mickey Callaway said they reversed course because he responded well to treatment.
"Much improved," Callaway said. "We’ll get him back to New York and get him checked out and go from there."
The reigning NL Cy Young Award winner, who had been scheduled to pitch Saturday, was coming off two shaky starts. He is 2-2 with a 3.68 ERA this season.
DeGrom said he’d been sick since Atlanta, with "whole body" soreness.
"I’ve had Tommy John before and done those tests, and everything feels fine with that," deGrom said of the 2010 surgery. "I’m not really worried about the spot it’s in, it’s just more being smart and not trying to go out there and do too much too early and risk a more serious injury."
DeGrom posted a 1.70 ERA in 32 starts last season. He signed a $137.5 million, five-year contract in March ahead of opening day.