"Right now, we have not made a decision," manager Jerry Manuel said.
The Mets have been concerned with the way Pelfrey has looked in his first two starts of the season. After Pelfrey gave up five runs in five innings Monday night against the Padres, the team sent him to have an MRI test. While the MRI showed no structural damage, doctors told Pelfrey he has inflammation that will have to be treated.
"We'll get this thing taken care of," said Pelfrey, who still hopes to make the Sunday start.
Pelfrey, who went 13-11 with a 3.72 ERA, was slotted in as the Mets' No. 2 starter, behind Johan Santana. Through two starts this season, he has an 8.10 ERA.
Manuel said if the Mets decide against pitching Pelfrey on Sunday, they'll call up a pitcher from the minor leagues to take his place.