Left-hander Pat Misch was added from Triple-A Buffalo to fill the roster spot, but the Mets intend to promote right-hander Dillon Gee for Sunday's start against the Atlanta Braves in Young's spot, manager Terry Collins indicated.
Misch's first usage should come as the backup for reliever D.J. Carrasco's spot start in Game 1 of Saturday's doubleheader.
The Mets backdated Young's DL trip to Monday. He will be eligible to return for the April 26 opener against the Washington Nationals in D.C., the same day as catcher Ronny Paulino, who is on the disabled list after being treated for anemia.
Left fielder Jason Bay, on the disabled list with a left rib-cage strain, could be activated Tuesday after playing a pair of rehab games with Class A St. Lucie this weekend.
Collins said Young will resume throwing this Tuesday after taking the weekend off to allow biceps tendinitis to calm. The manager added that the team's medical staff is confident there is no more severe issue and therefore no immediate need exists for an MRI or other imaging test.
The likely scenario is Ryota Igarashi is demoted before Sunday's game to clear room for Gee. Gee has made two starts for Triple-A Buffalo, going 1-1 with a 4.63 ERA.
Collins indicated Young was not going to make Sunday's start even if the series had been played without Friday's rainout forcing a doubleheader.
"He was not going to pitch tomorrow," Collins said. "... I didn't sleep very good. I woke up this morning and just said, 'I'm not going to do [use Young].' I just don't think it's worth the risk.
"All the medical people have said it's tendinitis. That's what it is. If you've ever had it, you know how painful it actually is. I just told Chris, 'Hey, look, another seven days, it'll be gone. It'll be over with.' And hopefully that will be the end of it. There's no sense of wearing and tearing it. I use him Sunday and he wakes up Monday and now he skips another start. I'm just not going to do that."