ST. LOUIS — Steven Matz is tentatively scheduled to pitch next Tuesday against the Marlins in what the Mets hope will be his return from shoulder tightness.

The lefty was placed on the disabled list this week (retroactive to Aug. 15) after an MRI exam revealed no structural damage in his shoulder, and manager Terry Collins expects Matz will need to miss just one additional start, on Thursday. The rookie was also scratched from a start last Friday in San Francisco.

“We’re hoping by Tuesday he will be OK again, but we’ve just got to wait and see,” Collins said before the Mets’ 7-4 win over the Cardinals on Tuesday night, their third straight victory.

The manager said he took the recent diagnosis as good news.

“Any time you’ve got a pitcher who has got, especially shoulder issues, you are on pins and needles not knowing how bad it’s going to be,” Collins said. “It came back that it was good news and hopefully a few days off and a little bit of rest will get him ready for next week.”

Seth Lugo, who replaced Matz in the rotation last week, is scheduled to face the Cardinals on Thursday.

Neil Walker’s wife, Niki, delivered the couple’s first child — a daughter, Nora Vail, who weighed 7 pounds, 3 ounces — at 3:06 a.m. Tuesday. Walker was placed on the paternity leave list, replaced by T.J. Rivera, and will speak to Collins on Wednesday about his return. Walker had previously indicated he planned to rejoin the Mets on Friday at Citi Field, but Collins indicated Thursday might be a possibility.

The Mets are 86-for-282 (.305) at the plate in the eight games of this road trip.