"Already battered with eight players on the disabled list, the Mets now have another injury worry.

Manager Jerry Manuel admitted yesterday that slugger Gary Sheffield's availability is in question beyond Thursday, pending the results of an imminent MRI exam on his sore right knee.

Sheffield will continue to DH through Thursday, when the Mets complete an interleague series in Baltimore. Manuel, however, isn't sure if the 40-year-old veteran can start playing the field again when the Mets return to NL rules next Friday at home against Tampa Bay.

It's a concern because Sheffield, despite his age, is the Mets' lone remaining power threat with Carlos Delgado out until at least the end of July because of right hip surgery. Manuel said Sheffield's knee problem started in late May during a series at Citi Field with the Marlins.

"I do know he's struggled the last week or so with that [knee pain]," Manuel said. "After that Florida series at home, he began to feel some discomfort there and has been trying to play through it for the most part." "