Bay, 33, left Monday's game in the eighth inning after feeling soreness in his rib cage, four innings after landing awkwardly in pursuit of a fly ball. X-rays taken during the game were negative, but an MRI exam administered Tuesday morning at Manhattan's Hospital for Special Surgery revealed the injury. Bay will do nothing more strenuous than ride a stationary bike until the pain in his ribcage subsides.
"It's extremely frustrating," he said. "There's really no other way to put it."
Pelfrey, 28, began experiencing soreness in his right elbow during Saturday's outing, his best in three starts this season. The right-hander said that although he felt discomfort at the beginning of each inning, it subsided as he continued to pitch. A precautionary MRI taken Tuesday revealed swelling around the joint.
The Mets were still awaiting a final diagnosis from that test late Tuesday afternoon, but were already making plans for Pelfrey to receive a second opinion from an independent specialist. Typically with elbow injuries, that means a trip to Alabama to see Dr. James Andrews.
"I take more pride than anything in taking the ball every fifth day," said Pelfrey, who had never previously been on the DL in his seven-year career. "Hopefully I get back as soon as possible."
The injuries are doubly frustrating for the Mets because of how well Bay and Pelfrey had been performing. Despite enduring regular scorn from the fans at Citi Field, Bay had rebounded from a weak start to hit .290 with all three of his home runs since April 13. He was 5-for-15 over his past five games, reaching base more than 44 percent of the time and significantly reducing his strikeout rate.
Bay's rib fracture is the latest of several significant injuries he has endured since joining the Mets on a four-year, $66 million contract. The left fielder suffered a serious concussion crashing into Dodger Stadium's outfield fence in July 2010, then strained his left intercostal muscle last spring and began the season on the DL.
Monday's injury occurred as Bay chased down Gregor Blanco's double in the fourth inning at Citi Field. Launching into a backward dive in an attempt to catch the ball on the fly, the left fielder tipped it with his glove, landed on his chest and appeared to plant his face in the turf. He needed a moment to collect himself after the play, but stayed in the game for another four innings.
Bay will remain in New York for the foreseeable future, until doctors clear him to begin baseball activities at the team's rehab complex in Florida. The best-case prognosis for his return is mid-May, though Bay could be sidelined significantly longer than that.
"They were very quick to not put a timetable on it, because everyone reacts differently," Bay said, referring to the team's doctors. "The good thing is it's a fairly small crack, so hopefully it won't take that long."
The timetable is even murkier for Pelfrey, who could be dealing with anything from a ligament tear to a bout of inflammation. The Mets will know more by Wednesday, when they receive the final results from Pelfrey's MRI.
Like Bay, Pelfrey had been thriving since mid-April, giving up two runs over his past two starts, a span of 14 innings. Even if it is minor, Pelfrey's injury will almost certainly prevent him from amassing at least 180 innings for a fifth straight season.
"Durability has been a hallmark of Mike's pitching for the Mets over the years, and something we've come to rely on," Alderson said. "But this is part of the reality of pitching as we know it."
To replace Bay, the Mets recalled Lutz from Buffalo, where he was hitting .333 with three home runs in 19 games. Though Mike Baxter and Scott Hairston figure to see increased playing time in Bay's absence, manager Terry Collins indicated that Jordany Valdespin -- a natural middle infielder who spent time late this spring taking reps in center field -- will receive regular opportunities against right-handed pitching. Lutz should fill in primarily as a right-handed-hitting infield reserve, capable of playing third and first base.
Carson, who took Pelfrey's spot on the active roster, will remain in the bullpen only for three games. The left-hander will shuttle back to Buffalo on Friday, when the Mets need a starting pitcher for their series opener in Denver. Because he is on turn in the rotation and already a member of the 40-man roster, right-hander Chris Schwinden is the overwhelming favorite to assume that spot.
For the Mets, the short-term result is a roster that includes four players who began this year in Triple-A, as well as 10 who opened last season in the Minors. Tuesday's starting lineup included four from that latter group, with Baxter replacing Bay in left field and Kirk Nieuwenhuis manning center.
Such is reality now for the Mets, who have endured myriad injuries to core players since 2009, spending much of last season in particular without injured stars David Wright and Ike Davis.
Said Collins: "We're just going to have to pick each other up, as we've done in the past, and move forward."