NEW YORK (WFAN) — The Mets’ beleaguered bullpen will have to make due without closer Frank Francisco for longer than expected.

Francisco, on the disabled list since late June with a strained oblique, recently suffered a setback during his rehab assignment. Mets manager Terry Collins said the closer has been shut down “from throwing … to get more more treatment on the oblique.”

“I don’t know if its square one,” Collins said, according to the New York Daily News. “But he’s got to throw some sides before he pitches in a game again, to see if this flares up.”

Meanwhile, right fielder Lucas Duda will have his ailing left hamstring examined on Monday.

“We’ll find out tomorrow how bad it is,” said Collins. “He’s been playing with it. It’s been bothering him a little bit.”

While one corner outfielder sits, another could soon be back. Jason Bay will be in the lineup again Monday for Triple-A Buffalo and could be activated as early as Tuesday.

“He needs at-bats,” said Collins. “This is about at-bats. I’m not worried about fatigue factor. He’s been out three weeks. He’s well-rested.”

Will the Mets have to make a move to bolster the struggling ‘pen? Be heard in the comments below…