Syndergaard reached for his right hamstring after throwing a pitch. Mets manager Mickey Callaway and an athletic trainer went out to check on Syndergaard, who quickly walked off the field with a bit of a limp. He was later diagnosed with a strain.
Robert Gsellman entered with New York leading 8-3. St. Louis scored three runs before the inning was over.
Syndergaard threw 102 pitches. He was charged with five runs, four earned, and six hits in six-plus innings.
Earlier in the game, plate umpire Brian O’Nora left after getting hit in the groin by a foul ball. Matt Carpenter fouled off a pitch from Syndergaard in the third inning, and the ball bounced up and hit O’Nora. He staggered but stayed on his feet, and was checked by a Mets athletic trainer.
The 56-year-old O’Nora initially remained in the game following a brief pause to gather himself. But a few pitches later, with Dexter Fowler at the plate, the veteran ump headed for the Mets’ dugout in discomfort with his hand covering his mouth.
In April 2013, an intestinal tear forced O’Nora to make a sudden exit from a Phillies-Mets game at Citi Field.