Mets lefty reliever Chasen Shreve is making it tough for Mets decision makers this spring.

The 31-year-old non-roster invite returned to the Mets this spring because of their need for a lefty out of their pen. With an excellent spring so far, the Mets might be forced to bring him onto the 40-man and even the main roster when the season begins.

“Nobody said we have to carry a left-hander,” manager Buck Showalter said on Sunday. “It’s not a written rule.”

New York doesn’t have a lefty in their projected starting rotation and they don’t have a left-hander on their 40-man roster either.

Shreve has been lights out through spring training and showed off again on Tuesday night against the Marlins when he struck out two batters in one inning of work. In three outings this spring he’s yet to allow a baserunner and has struck out four.

His main competition for a role on the Mets this season is veteran lefty Alex Claudio.

“All of them have represented themselves well, as advertised — not just [Shreve] and Claudio, but there are some other options here,” Showalter said.

Claudio has three appearances this spring as well, striking out three and allowing two hits.

Shreve could be the Mets bargain replacement for Aaron Loup. Loup left the Mets to sign a two-year, $17 million deal with the Los Angeles Angels. Loup was another bargain find for the Mets in 2021 signing the journeyman to a one-year, $3 million deal that resulted in a season where his ERA was under 1.00.

Shreve has major league success. Last season with Pittsburgh he had a 3.20 ERA in 56 innings. Now he’s back in New York eyeing a role that will put him in a division against some of the best left-handed hitters in the game like Juan Soto, Bryce Harper, and Matt Olson.

“That’s a reason why I picked the Mets. I knew they needed left-handed help,” Shreve said. “I’ve been in New York most of my career. So it was somewhere I wanted to come back to for sure at some point, and it just worked out.”

Now the Mets need to decide if he’s the best man for the job. Rosters are expected to expand to 28 through May 1 which might make the choice easier for the Mets but they’ll need to find room for him the rest of the season if he performs well.