Mets starter Jon Niese left Thursday's start with a shoulder injury. (Scott Cunningham/Getty Images)
Niese's discomfort became apparent when he winced after a fourth-inning pitch to Tyler Pastornicky. The Mets' training staff immediately came out to check on Niese, who then left the game.
According to ESPN.com's Adam Rubin, Niese has been battling what the team has labeled left-shoulder tendinitis. In 14 starts so far this season, Niese is 3-6 with a 4.32 ERA. He has 49 strikeouts and has walked 33 batters in 77 innings.
Niese's injury could solve the Mets' rotation surplus problem, however. The Mets were planning on temporarily shifting to a six-man rotation with top prospect Zack Wheeler debuting this week.