NEW YORK -- Saturday afternoon's pregame scouting meeting involved right-hander Chris Young, catcher Josh Thole and Mets pitching coach Dan Warthen, all as planned. But also invited was right-hander Dillon Gee, on this day otherwise known as Plan B.

Ultimately, it was Gee who started Saturday's game against the Dodgers after Young was a late scratch because of tightness in the back of his right shoulder. Young will undergo an MRI on Sunday morning and may be headed for a second stint on the disabled list.

As a hedge, the Mets have asked left-hander Pat Misch to fly south from Triple-A Buffalo. But the team will only activate Misch if Young lands on the DL.

"I expect that Misch will be added to the roster," Mets general manager Sandy Alderson said late Saturday night. "But the other half of that move we'll figure out in the morning."

Young, who missed more than two weeks last month with right biceps tendinitis, originally felt tightness in his shoulder during a routine bullpen session earlier this week. He drove to the ballpark on Saturday unsure if he would be able to pitch, leading the Mets to prepare Gee just in case.

Less than a half hour before game time, as he was long tossing in the outfield, Young informed the Mets that he could not pitch. And Gee became the team's new starter.

"Really, the only thing that mimics the pain is throwing a baseball, and throwing a baseball with some effort," Young said. "If I had gone out there tonight, I would have been pitching 78 miles an hour. The competitor in me wanted to be out there, wanted to do it. But Dillon gave us a much better chance to win, there's no doubt about it."

Though Young felt no pain during a series of shoulder tests earlier this week, pitching presented a problem. A pitcher who prides himself on knowing his body after undergoing multiple shoulder surgeries in recent years, Young seemed utterly baffled by this latest setback, calling it muscle tightness or "fatigue."

"At this point, I have no idea," Young said. "Hopefully it's nothing more than that."

When healthy this season, Young has been the team's best pitcher, posting a 1-0 record and 1.87 ERA in four starts. But remaining healthy has presented a significant challenge for Young, who has made just 22 starts since the start of the 2009 season.

If the Mets do place Young on the disabled list, Gee will step into his rotation slot, with Misch working out of the bullpen.

In four starts for Buffalo, Misch was 0-2 with a 6.46 ERA, most recently pitching six innings last Tuesday.