Syndergaard was scratched from a start Thursday with biceps and shoulder discomfort. He had been scheduled for an MRI on Friday but declined to have one after throwing a bullpen session.
“I think I know my body best,” Syndergaard told reporters. “I’m pretty in tune with my body, and that’s exactly why I refused to take the MRI.”
On Saturday, Mets general manager said it was unusual for a player to refuse an MRI, but the team couldn’t force him to undergo the exam.
Syndergaard allowed five runs on five hits in the first inning and walked his first two batters of the season, one intentionally. He threw 38 pitches before leaving the game.
The Associated Press contributed to this report.