NEW YORK -- Noah Syndergaard could not hide a noticeable limp as he walked off the field in the seventh inning Saturday, clutching the back of his right leg. Hours later, the Mets had “no idea” as to the severity of an injury that could have a major impact on their season.

Syndergaard exited the Mets’ 8-7 win over the Cardinals with a right hamstring strain. The Mets plan to reevaluate him on Sunday morning. When reporters entered the postgame clubhouse late Saturday night, Syndergaard -- already in street clothes -- bolted for a back room, telling a member of the public relations staff that he was going to receive treatment. Through a team spokesman, he later declined comment.

“We really have no idea at this point,” manager Mickey Callaway said.

Though Syndergaard was not at his best in the game, allowing five runs in six-plus innings, he took the mound at 98 pitches in the seventh with a lead. Syndergaard allowed a leadoff hit to Yairo Munoz and a stolen base two pitches later, clutching his right hamstring as he stepped off the mound on that play. He walked off the field moments later, following a brief discussion with Callaway and trainer Brian Chicklo.

“That deep in a game, if he feels anything, you get him out with a five-run lead,” Callaway said.

Given as much time as he needed to warm, reliever Robert Gsellman entered and allowed three runs in the seventh, two of them charged to Syndergaard.

The Mets will now wait to see how serious Syndergaard’s issue is. Even if it’s relatively minor, it is an injury they can ill afford, considering how perilously thin their rotation depth remains. The team recently converted one of its top starting options, Chris Flexen, to relief, and designated another, Hector Santiago, for assignment. A third, Corey Oswalt, is on the injured list at Triple-A Syracuse.

Less orthodox options include Seth Lugo, who has started for the Mets in the past but is not stretched out enough to provide more than three or four innings, and Anthony Kay, the club's No. 7 prospect per MLB Pipeline who earned a promotion to Triple-A Syracuse this week but whom team officials feel is not quite ready for the big leagues.

If needed, the Mets’ best option to fill Syndergaard’s spot may be Walker Lockett, a rookie whom they acquired this offseason for catcher Kevin Plawecki. After sitting out much of the early season due to an arm injury, Lockett has posted a 3.28 ERA in four games with Syracuse.