Parnell is out for the season after Tommy John surgery but when he rehabs next year will do so as a closer.
"When Bobby Parnell comes back, he will be pitching during his rehab as if he's the closer, because that's certainly in our plan when he gets back,” Terry Collins told reporters before Friday's game. "When Bobby's ready, we've got a nice problem on our hands. But looking that far ahead, we certainly can't have any idea who is the guy pitching in the ninth."
Mejia, who has 18 saves and a 3.10 ERA out of the bullpen since taking over for Parnell in April, has fought through a multitude of injuries that has slowed him down. Durability remains his biggest question mark as the Mets are unsure if he can make it through an entire season as a closer.
Parnell, 29, moved into the closer role last year and had 22 saves and a 2.16 ERA. He pitched 50 innings last year and struck out 44 batters. Parnell pitched one inning on opening day, blowing the save in a 9-7 loss on March 31. He was diagnosed with a torn ligament in his elbow and underwent surgery to repair it in early April.