The two-time Cy Young Award winner said he felt good Thursday, two days after leaving an intrasquad game early because of back tightness. A precautionary MRI came back clean, and deGrom thinks he simply might have "slept wrong."
"Having everything checked out and checking all those boxes definitely makes me feel better about this situation," he said.
"I think it was just kind of a random thing as far as, woke up a little stiff. ... These past few days I've felt good."
He hopes to throw Friday and still believes he can get another tuneup of 60-65 pitches -- perhaps now in Sunday's exhibition game against the Yankees instead of Saturday -- before starting the season opener July 24 versus Atlanta as scheduled. The right-hander said he might be able to throw only about 85 pitches on Opening Day rather than the 100 or so he was targeting, but his goal remains to take the ball.
Rojas, however, said the team is taking a day-to-day approach as deGrom receives treatment and will need to reassess.
"See how he feels tomorrow," Rojas said. "We have to get through this couple of days at least."
The Mets already are without No. 2 starter Noah Syndergaard. He had Tommy John surgery and will miss the entire season, which was trimmed to 60 games because of the coronavirus pandemic.
Meanwhile, Mets second baseman Robinson Cano is back with the team after missing a couple days because of personal issues.
The 37-year-old Cano said he wants to keep the reasons for his absence to himself. He is hoping to be ready for Opening Day when the Mets host the Atlanta Braves on July 24.
"I went home and I spent the time in the Dominican [Republic] with my family," Cano said. "I don't know if you guys know; I do have my own field there where I trained every day, and I had the chance to work there with my dad and be able to get my work in and stay in shape."
Cano is headed into his second year with the Mets after he was acquired in the December 2018 trade that sent top prospect Jarred Kelenic to Seattle. Cano hit .256 with 13 homers and 39 RBIs in 107 games last season.
Rojas said deGrom left Tuesday night's camp outing after only one inning at Citi Field, giving the club a scare.
"What was weird is it was just out of the blue," deGrom said Thursday on a video conference call. "This was nothing like one pitch -- it just was something that didn't loosen up."
"I wasn't too worried because I didn't think it was serious," he added. "If that was a regular game, I wouldn't have said anything. But as far as it being a spring training game, or summer camp game, there was no reason to push through something and risk actually injuring myself. So like I said, it was out of abundance of caution and just trying to play it smart."
Last year, deGrom won his second consecutive National League Cy Young Award after going 11-8 with a 2.43 ERA in 204 innings. He led the National League with 255 strikeouts.
Preseason back stiffness has bothered deGrom in the past, bumping his initial start from Opening Day to the second game of the year in 2018. But it hasn't sidelined him for long.
Information from The Associated Press was used in this report.