NEW YORK -- Mets ace Jacob deGrom was pulled from his start Sunday after throwing two warm-up pitches before the sixth inning after experiencing tightness in his right side.

The Mets later said that deGrom will undergo an MRI to make sure the tightness, which is more in his lower back on his right side, isn't an indicator of a serious injury. DeGrom was pitching for the first time since skipping a start due to discomfort in his right lat. The Mets said he was removed from Sunday's game for precautionary reasons.

"He's going for an MRI, just to see what's going on there, to see how he is, have a clear view. Right-side tightness is what we have from our medical staff here, more so in his lower back area, on the right side. They're taking a look, so once we get the results back, we'll know how he is," manager Luis Rojas said after the Mets' 4-2 victory.

Rojas said deGrom's discomfort Sunday is "different" than what he was experiencing earlier this week when he skipped a start as the tightness is "more in the lower back area, rather than a little higher where it was." Rojas said deGrom was experiencing "no pain whatsoever. He said it's just tightness. That's what he told our trainer."

Rojas would not speculate on what the next steps for deGrom are, saying he wants "to leave it to our medical staff and team doctor, after they take a closer look and see what he had."

DeGrom did not talk with reporters after the game.

The two-time NL Cy Young Award winner threw 68 pitches over five innings against the Arizona Diamondbacks, allowing one run, but he called for a trainer when he felt discomfort trying to get loose before the sixth. He left with the trainer and went straight to the clubhouse, and it was not immediately announced what caused him to leave.

DeGrom struck out six and allowed one hit. He was perfect through four innings before struggling in the fifth, when he allowed a run.

The right-hander walked three in the inning, just the second time in his career he's done that. His previous three-walk inning was May 13, 2018, at Philadelphia. He was pulled after one inning in that game, his first back from the injured list.

New York led 2-1 when he exited Sunday, with deGrom scoring the second run after reaching on a perfectly placed bunt single in the third inning.

He was replaced by right-hander Miguel Castro and followed by fellow relievers Jacob Barnes and Edwin Diaz, who got the final five outs to earn a save in the Mets win, their fifth straight.

DeGrom improved his record to 3-2 on the season while his ERA rose to 0.68.

ESPN's Bradford Doolittle and The Associated Press contributed to this report.