Harvey is unlikely to pitch again this season, general manager Sandy Alderson said. Tommy John surgery may be required, although a decision will wait two to three weeks, until swelling subsides and a clearer assessment of the extent of the tear can be determined.
Harvey expressed hope he could avoid surgery by strengthening the area around the ligament tear, although Alderson noted pitching through partial tears often is unsuccessful and suggested the procedure ultimately might be required anyway.
Tommy John surgery generally requires a 12-month recovery time and would cost Harvey most if not all of the 2014 season.
Harvey was sent Monday morning to the Hospital for Special Surgery in Manhattan after complaining of forearm discomfort following a 102-pitch start Saturday against the Detroit Tigers. As part of that exam, Dr. David Altchek had Harvey undergo an MRI that revealed the UCL tear.
"Doctors will always tell you that if you could avoid surgery you should," Alderson said. "However, we have had situations in the past -- not just here, but across baseball -- where the conservative approach doesn't work, and what you end up with is a loss of time and therefore a delay in recovery. That all has to be taken into account. We're all aware of what [a] delay might cause, and so we will be monitoring the situation. And I'm sure Matt will be making a decision in conjunction with us that takes that into account."
Said Harvey: "I'm going to do everything I can so I don't have to get surgery."
Agent Scott Boras noted the need for surgery will not be clear until the extent of the tear becomes fully apparent on follow-up imaging once the swelling subsides.
"When you're talking about the term 'partial tear,' you're talking about 5 percent to 95 percent," Boras said. "You have to get in and get the specifics and get more information medically before we can really make a determination as to what we're dealing with. There's a lot of swelling in there now. ... I've had situations with no surgery. I've had situations where the doctors recommended surgery."
Harvey said he had been experiencing forearm tenderness for a month or two but had been getting treatment and did not believe any major issue existed.
"Obviously it was the last thing I was expecting when I went in this morning," Harvey said, referring to the medical exam. "I haven't had shooting pains down my hand or in my elbow at all. It's mostly been forearm tightness. It's something, obviously, I could pitch through. It just so happens this last start was a little bit more uncomfortable than normal, and I decided it was in my best interest to get it checked out. I was hoping for ... tenderness or just some stiffness and swelling of the muscle area, and it obviously turned out to be something else. That was definitely a shock."
Harvey is 9-5 this season with a 2.27 ERA and 191 strikeouts. He ranks second in the majors in ERA, third in WHIP and fourth in strikeouts. He started July's All-Star Game at Citi Field.
Right-hander Carlos Torres will enter the rotation in Harvey's spot.
The Mets have been vigilant in monitoring Harvey's workload in order to reduce his susceptibility to injury. They cut short his 2012 season after a Sept. 19 start to cap his workload between the majors and minors at 169 1/3 innings. This year, they planned to halt his workload at roughly 205 innings. Boras said he believes the Mets have acted responsibly.
"With his age, and he's a power pitcher and the whole thing, this is a very normal course for a major leaguer," Boras said. "It's how you develop players. There's nothing on that front that I think is an issue at all."
The Harvey blow came on the day right-hander Jeremy Hefner sought a second opinion from Dr. James Andrews in Birmingham, Ala., about the need to undergo Tommy John surgery for an MCL tear. Hefner will proceed with the surgery, which had been recommended by Mets doctors, according to a source.
On a positive note, third baseman David Wright is progressing from a Grade 2 right hamstring strain. He is expected to travel from New York to the Mets' complex in Port St. Lucie, Fla., on Thursday to ramp up baseball activities. Wright began running outdoors and taking grounders at Citi Field this weekend.
Catcher John Buck knows the Mets will have to adjust.
"Anytime you're going out there without your ace who is kind of contending for a Cy Young and all that good stuff, a starter that you anticipate winning every week, [it's tough]," he said. "It's obviously a downer but it's past us now, we have to keep moving forward like we did when David went down."
If Harvey were to miss the 2014 season, it would be an enormous blow to the Mets.
Since Alderson's regime took over three years ago, it has been building toward that season signaling a return to competitiveness. Johan Santana, Jason Bay, Frank Francisco, Buck and Shaun Marcum -- making roughly $70 million combined this year, with buyouts -- come off the payroll, allowing the Mets to reenter free agency. And the Mets have built a solid nucleus of young starting pitching centering on Harvey and rookie Zack Wheeler.
"It's unfortunate from Matt's point of view and it's unfortunate from the standpoint of the organization," Alderson said. "There's no question about that. On the other hand, these are the kind of things that happen in the game. The successful teams, the successful organizations, respond to these setbacks. That's exactly what we have to do. This is not a career-ending injury under any stretch of the imagination.
"In terms of our timetable, it certainly will have an impact. We're fortunate we have a lot of pitching depth in our organization, so that gives us perhaps a leg up on responding to this. But this is what many successful teams must go through from time to time. For us to expect not to have to go through it from time to time would be unrealistic.
"This news was tough today. There's no question about that. And the full implication of it probably has not yet been felt. But we have to respond. And we will."
Information from ESPNNewYork.com's Matt Ehalt was used in this report.