"Last start, I felt fine," deGrom said. "I actually felt like I got stronger at the end of the game. And then just playing catch these past couple of days, I felt a little something in there."
Rookie deGrom is 6-5 with a 2.87 ERA in 16 starts. He's posted 94 strikeouts in 100 1/3 innings.
Right-hander Rafael Montero was recalled from Triple-A Vegas to take deGrom's place in the rotation. Montero will start Tuesday against the Nationals at Citi Field.
The 23-year-old Montero has posted an 0-2 record and a 5.40 ERA in four starts with the Mets this season. Manager Terry Collins expects him to make at least two starts this time around.
"We wouldn't bring [Montero] up for just one start,'' said Collins. "He'll make two [starts]. All he has to do is be himself and throw strikes.
"He's a strike-throwing machine. The first time he was here, he nibbled. If he's himself, throwing strikes, he's real good.
"The first time he was up, I told him: 'What gets you to the Major Leagues is what keeps you in the Major Leagues.' For him, it's throwing the ball over the plate.''
Montero has recorded a 6-3 record and a 3.28 ERA in 15 starts at Triple-A Las Vegas. In his last two starts, wins over El Paso at home and Sacramento on the road, he threw a combined 14 2/3 scoreless innings, with batters hitting .085 against him.
"[Montero] certainly has the stuff that will play in the Major Leagues,'' said Collins. "He needs to throw strikes, and if he does that, he'll be here for a long time."