NEW YORK -- Whether by plan or by happenstance, the time has arrived for the New York Mets to get a look at two of their top pitching prospects -- "Super 2" deadline be darned.

Right-hander Rafael Montero made his first major league appearance Wednesday night, taking the rotation spot of right-hander Jenrry Mejia, who was bumped to the bullpen. Montero allowed three runs over six innings and took the loss as the Mets fell to the New York Yankees 4-0 at Citi Field.

Montero will be followed to the mound Thursday by another right-handed debutant, Jacob deGrom, who was promoted to the Mets on Monday with the expectation he would pitch out of the bullpen. Instead, deGrom was thrust into the rotation when right-hander Dillon Gee suffered a right lat injury while throwing a bullpen session Tuesday.

It is the first time ever starting pitchers have made their major league debut for the Mets in back-to-back games. And while the Mets may have preferred to make that bit of history on a smaller stage than the Subway Series, manager Terry Collins said Wednesday afternoon he welcomed the baptism-by-fire opportunity.

"You're going to look at a rotation of these young kids coming up here, and you can't have any fear -- I mean, if you're going to pitch here, this is what it's going to take," Collins said. "And these young guys have shown that they have the ability and the qualities it takes to pitch at the major league level."

If Montero, who was 4-1 with a 3.67 ERA and 41 strikeouts in 41 2/3 innings over eight starts at Triple-A Las Vegas, and deGrom, who went 4-0 with a 2.58 ERA and 29 strikeouts in 38 1/3 innings over eight starts at Las Vegas, are as good as the Mets hope, the team will end up paying more for their services faster than it would have if it waited to promote the duo.

Generally, the "Super 2" deadline falls in mid-June, the point at which prospects can be promoted from the minor leagues without the parent club worrying about them qualifying for arbitration after their second full season in the bigs.

Coincidentally or not, the Mets waited until after the Super 2 deadline each of the last two seasons with ace right-hander Matt Harvey, who made his major league debut July 26, 2012, as well as promising right-hander Zack Wheeler, who reached the bigs June 18, 2013.

"When we brought up Harvey and Wheeler, it was really about their readiness for the big leagues," Mets general manager Sandy Alderson said Wednesday afternoon. "There's no question that one always has one's eye on years of control and major league service as well as 'Super 2' status.

"But in the overall scheme of things, is the player ready or not ready? And bringing up Montero and deGrom really is about are they ready or are they not ready."

Alderson acknowledged, though, that the Super 2 deadline might have played into the Mets' decision-making had the need for rotation stopgaps arisen a few weeks from now. It is interesting to note that right-hander Noah Syndergaard -- the Mets' top prospect and one of the most promising young pitchers in the game -- remains at Triple-A Las Vegas, where he is 4-2 with a 3.92 ERA and 46 strikeouts in 43 2/3 innings.

Alderson declined to identify a timetable for Syndergaard, partially because he doesn't want to feed the tabloid beast ("I don't want to create a 'Noah Watch'") but mostly because the last few days have taught him he will never know when he might have to deviate from the plan, whatever it may be.

"Look, who knows what will happen?" Alderson said. "We now have two guys in the rotation who weren't in the rotation yesterday, and what was once tremendous depth is now getting more and more shallow in terms of resources.

"Noah's done a nice job at Triple-A. I wouldn't say that anything he's done so far would exclude him (from a promotion) six weeks, two months from now. But that's not part of the plan, if such a thing exists."