Syndergaard only pitched 1 1/3 inning on Sunday before being removed because of the injury. The Mets did not provide a timetable for his injury, but Steven Matz suffered a similiar injury in 2015 and missed just over two months.
For now, the injury opens up the roster spot for Sewald, the 51s’ closer.
Sewald is 1-0 with a 2.08 ERA in eight games this season. He has compiled four saves and opponents are hitting .206 against him.
In his brief time with the Mets earlier this season, he gave up two runs in 1 1/3 innings pitched across two outings.
Manager Terry Collins told reporters in Atlanta that Rafael Montero and Sean Gilmartin are options to start on Friday in Syndergaard’s absence, though Montero, who has made two starts in Las Vegas, seems to be the more likely option of the two.
Contact Betsy Helfand at email@example.com. Follow @BetsyHelfand on Twitter.