The warning bells went off when the Mets posted a lineup on Wednesday morning and Michael Conforto was not in it.

Against a righthander? When he went into the day batting .330? It’s not as if the 24-year-old needs a rest day, especially since the whole team is getting one on Thursday.

It turns out Conforto has been battling a “tight” left hamstring for a couple of days. So rather than let this become one of those Mets injuries that goes from nothing to a big something, manager Terry Collins chose to sit Conforto and hope that he will be 100 percent by Friday, when the Mets open a series in Milwaukee.

“I’m getting treatment on it,” said Conforto, who singled as a pinch hitter in the eighth inning of the Mets’ 6-5 loss to the Giants at Citi Field. “With all the injuries we’ve been having, just want to make sure that nothing more serious [is happening]. It’s not really all that bad. I feel pretty good. Just trying to stay ahead of it. A couple days off should be good for me.”

The same goes for shortstop Asdrubal Cabrera, who said he expects to return to the lineup on Friday as his injured left thumb heals. Cabrera struck out with the bases loaded as a pinch hitter in the sixth.

Lucas Duda might be back this weekend as well, Collins said. Duda went 1-for-3 with a walk and a home run as the designated hitter in his fifth rehab game for St. Lucie (A).

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T.J. Rivera, who has been filling in ably for Duda, went 1-for-5 and is batting .300.

Got Wilk?

Lefthander Adam Wilk, who was banged around by the Marlins as an emergency replacement for the suspended Matt Harvey on Sunday, was claimed off waivers by the Twins.