Syndergaard limped off the mound while holding the back of his right leg in the seventh inning alongside trainer Brian Chicklo. Following the game, Syndergaard refused to discuss his injury with reporters, according to Anthony DiComo of MLB.com.
The 26-year-old has a 4.55 ERA with 93 strikeouts over 95 innings this season.
If Syndergaard misses any significant time, the Mets could be forced to stretch out Wilmer Font (5.46 ERA) or Chris Flexen (11.12 ERA) again. The two right-handers have combined to start four games in 2019 with mostly underwhelming results.
Veteran starter Ervin Santana, who joined New York on a minor-league deal last month, could be another option. He's currently with the team's Single-A affiliate in Port St. Lucie, Fla.