Double downer for DL’d Lugo, Matz

The Mets’ vaunted pitching depth maybe isn’t so deep.

Seth Lugo, who was placed on the disabled list before Monday’s game with what previously was termed “arm fatigue,” will get a second opinion on his right elbow for an undisclosed issue, he revealed after the Mets beat the Braves 6-0 at Citi Field.

The righty had an MRI exam over the weekend, and a club source said the test result may have found a significant prob- lem. Lugo said he will be re-examined Tuesday in New York.

Manager Terry Collins said he expects Lugo will be sidelined for at least “a couple of weeks.”

Earlier in the day, Steven Matz revealed he has a strained flexor tendon in his left elbow — a more specific diagnosis for his DL stint than the vague “elbow irritation” that previously was disclosed by the club.

Matz, who was shut down from throwing for three weeks, received a PRP injection.

“Personally, I love to play baseball, and now I can’t play baseball,” Matz said. “Professionally, it’s my job, and now I can’t do it. On both ends, it’s real unfortunate.”

Once Matz is cleared to resume throwing, he still will have to build up arm strength and need minor league starts, likely making a mid-May return his best-case scenario.

“Thankfully, it’s not anything more serious,” said Matz, who underwent Tommy John surgery early in his minor league career. “So I hope that I can come back and help the team when I’m ready, but there’s nothing I can do, I feel like.”

Lugo’s elbow discomfort emerged after returning from representing Puerto Rico in the World Baseball Classic. The right-hander said he may have pushed too hard in his final Grapefruit League appearance in an attempt to solidify a roster spot.

The Mets entered spring training with seven starters for five spots but now have only a full rotation of Noah Syndergaard, Jacob deGrom, Matt Harvey, Zack Wheeler and Robert Gsellman.