Mejia was unable to get clearance from doctors to throw, however, and was unavailable during Friday night's 6-2 win over the Padres. Manager Terry Collins expects him to miss Saturday as well.
"Jenrry's back is fine," Collins said Friday afternoon. "Feels a lot better today. He is trying to see how he feels throwing-wise."
The situation wasn't as sunny after the game.
"He's got some stiffness in there, and they gave him some medication to relax the area a little bit," Collins said. "But he's got some swelling. He said it'll probably be a day or so before he's going to be available.
For as long as Mejia is unavailable, the likely option to close is right-hander Jeurys Familia, who pitched a scoreless ninth on Friday. Familia has two saves in three career opportunities, two of which came last month.
He recorded the final five outs in a 5-0 Mets win over the Phillies May 28, then blew a ninth-inning lead May 31 against Philly in a game New York went on to win, 5-4, in 14 innings.
Much is made of a so-called closer's mentality -- i.e., pitching the ninth inning of a close game requires a certain psychological makeup that not every hurler possesses -- but Familia doesn't think there is much to it.
"Every time I go to pitch, it doesn't matter what inning I'm throwing," Familia said. "For me, first inning, second inning, seventh inning, eighth inning, ninth inning -- it's all the same. You just have to go out there to throw strikes to get the hitter out.
"Just go out there and try to get three outs."
Best-case scenario for the Mets, though, is having Mejia healthy enough to get those three outs.
"Everything's going to be [OK]," Mejia said Friday afternoon before walking away with a big smile.