Matz not all, folks! Lefty due back soon

ST. LOUIS — It’s not often the Mets get good medical news on one of their starting pitchers.

But that’s what they got before Tuesday’s series opener against the Cardinals.

They found out that Steven Matz, who was placed on the disabled list Monday with shoulder tightness, could be back in action next week at Citi Field.

“We’re hoping by Tuesday he’ll be ready to go again,” Terry Collins said. “I take it as good news. Any time you have a pitcher who has, especially, a shoulder issue, you are on pins and needles not knowing how bad it is going to be.

“(The results) came back and that was good news. Hopefully a few days off and a little bit of rest, we’ll get him ready for next week.”

Having back-dated his time on the DL to the day after Matz’s last start, Aug. 14, the Long Island lefty will be eligible to return on Tuesday at home against the Marlins.

There has been some chatter among Mets fans who have given up on the year about shutting down Matz, but the lefty’s shoulder has no structural damage, just a “mild strain.”

And the Mets know they will need the young pitcher if they are to stay in the wildcard race. As it is, they are fighting just to stay in the mix.

After their 7-4 win on Tuesday, they are are 3.5 games behind the Cardinals (four in the loss column) for the second wild card.

Lefty Jon Niese, whom the Mets traded away in December and took back as a chance to dump reliever Antonio Bastardo, started the game but injured his knee and exited after facing just four batters.

Jacob deGrom, coming off the worst start of his Met career, takes the mound Wednesday, and Seth Lugo is slated for his second major league start against Adam Wainwright on Wednesday. For a team that has been built around its starting power arms, this could be considered dire straits.

Matt Harvey is out for the season after surgery for Thoracic Outlet Syndrome and Zack Wheeler’s return from 2015 Tommy John surgery is likely not going to happen until 2017.

So, can the Mets win without the dominant pitching that got them to the World Series last season? Not even Collins is sure.

“We haven’t hit, so it’s certainly hard to say, but yeah, we have the potential to do it with the power in our lineup,” Collins said.

AP Wilmer Flores swats threerun homer in first and smiling Robert Gsellman (inset) doesn’t seem fazed when he’s called on to replace Jon Niese, who manages to get just one out before hurting his knee. In his major league debut, Gsellman throws 3.2 solid...