The Mets on Monday also skipped Jacob deGrom's scheduled start at Las Vegas and called him up after defeating the Yankees, 9-7. A right-hander, deGrom will join the bullpen on Tuesday, with Gonzalez Germen landing on the disabled list due to illness.
The moves come less than a week after the Mets called up infielders Wilmer Flores and Eric Campbell to start at shortstop and come off the bench, respectively, turning over a significant chunk of the active roster.
"The basic question that we ask ourselves every day is, 'What gives us the best chance to win?'" general manager Sandy Alderson said.
Apparently, the Mets believe it is high-upside youth. Montero, the organization's second-ranked player on MLB.com's 2014 Prospect Watch, was 4-1 with a 3.67 ERA at Las Vegas. He threw 5 1/3 no-hit innings in his final start there.
Though not as well regarded as uber-prospect Noah Syndergaard, Montero has close to a full season's worth of experience at Triple-A, with little left to prove at the Minors' highest level. Across 24 starts in the hitter-friendly Pacific Coast League, Montero has posted a 3.25 ERA with 119 strikeouts and 43 walks. Though he did not sign until age 20, extremely late for a Dominican free agent, Montero flew through the Minors in three-plus seasons.
"We think he's ready now," Alderson said, noting that Syndergaard boasts neither the experience nor the Triple-A track record of Montero. "I think everybody in our system thought that he was ready. That doesn't mean he'll have a positive result on Wednesday, but we're confident that Montero is somebody who can be successful long term."
The Mets also believe deGrom is ready, considering he has outperformed even Montero at Las Vegas. The organization's 13th-ranked prospect, deGrom was 4-0 with a 2.58 ERA at Vegas. He has never pitched out of the bullpen as a professional, though considering the organization's pitching depth -- in the rotation, Dillon Gee, Jon Niese, Zack Wheeler, Matt Harvey, Syndergaard and Montero are all ahead of him on the depth chart, with all but Gee under team control for at least four more seasons -- deGrom was a strong bet to end up there at some point.
His promotion Monday, along with Mejia's assignment to the bullpen, came more out of need than anything -- particularly with Germen slow to recover from a stomach virus. Lacking reliable bullpen arms, the Mets turned immediately to Mejia in Monday's win, leaning on him for four critical outs. Though Mejia was cruising, Mets manager Terry Collins said he did not consider leaving the right-hander in for the ninth.
Having made his big league debut four years ago as a reliever, Mejia has yo-yoed between the rotation and bullpen for nearly a half-decade. He stated many times along the way that he prefers starting, but Alderson called Mejia "the best resource to satisfy" what he sees as "a need in the bullpen" now.
"I know I am a starter, and they know I like to start," Mejia said. "But I always want to help my teammates. I'll go out there and be a reliever."
"He handled the conversation we had today extremely well," Collins said of Mejia. "He said, 'I'll do the best I can.'"
Because Mejia is on an innings limit of roughly 125 this summer, the Mets would have converted him to relief at some point anyway. So they considered it logical to do so now, with Mejia posting a 9.82 ERA over his last three starts.
Mejia could rapidly work his way into the Mets' uncertain ninth-inning situation, though Jeurys Familia and Vic Black are also prime candidates to close if veteran Kyle Farnsworth continues struggling.
"I think he's committed to the challenge at this point," Alderson said of Mejia. "I think he knows what his potential might be in the bullpen. So at this point, I think he's willing to accept that challenge."