Niese is currently doing pool work in Port St. Lucie, Fla., and is "not close" to returning, according to assistant general manager John Ricco.
"That midsection is kind of tricky, so we've just got to wait until he's pain-free," Ricco said. "When he sneezes, he feels it. It's not a sharp pain, but he still feels something in there, so we're not progressing him until he totally feels good."
Regardless, needing roster space, the Mets will not transfer Niese to the 60-day DL this week, keeping open the possibility that he could still return. The same goes for outfielder Scott Hairston, whose return from a strained left oblique is likewise not imminent.