Against all odds, it turns out the Mets' season actually had room to get worse.

On Monday, the team announced that star pitcher Matt Harvey was diagnosed with a partial tear of the ulnar collateral ligament in his throwing elbow. General Manager Sandy Alderson said Harvey is unlikely to pitch again this season — and given the nature of the injury, it's possible Harvey will miss all of next year as well.

The UCL stabilizes the elbow to mitigate stress when that joint twists and bends. Repeated use — and particularly excess stress caused by fatigue and poor mechanics — can create tiny tears in the ligament that gradually build into one large tear.

"The No. 1 risk factor for UCL injuries is poor mechanics," orthopedic surgeon James Andrews told ESPN. "The No. 2 factor is overuse. And if you overuse with poor mechanics, you're doomed."

The extent of Harvey's injury is not yet known. The Mets described it as a "partial tear," and said they would wait a few weeks for swelling to subside before determining how to move forward.

"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," Harvey's agent, Scott Boras, told ESPN New York, adding that a partial tear was highly ambiguous because "you're talking about 5 percent to 95 percent."

There are two options for treating UCL injuries, a surgical and non-surgical approach. The Mets have said they would like to try the non-surgical route first, having Harvey build up arm strength around the tear and then letting the rift repair itself.

However, surgery is typically needed in the case of pitchers. The Johns Hopkins University School of Medicine cautions, "Once the ligament has torn, it does not really heal well enough to allow a return to throwing." And as Yahoo's Jeff Passan points out, history has shown that, outside of a very small group of exceptions, "rehab of any sort of tear does not work."

Alderson himself conceded that point Monday, saying, "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."

The surgical fix for UCL injuries is a highly invasive procedure with a lengthy recovery time. Called Tommy John surgery, it involves reconstructing the torn ligament using a tendon from elsewhere in the body, often the forearm or wrist.

The recovery time for Tommy John surgery is usually 12 to 18 months. Though the surgery is severe and the recovery time quite long, 92 percent of players are able to resume playing at their old level for at least a year.

Though some pitchers never return to their previous form, others come back as if nothing had ever happened, or even begin throwing harder than they did before the surgery. Nationals phenom Stephen Strasburg underwent Tommy John surgery in 2010 and missed almost all of the next season, but returned in 2012 with an All-Star year. And Red Sox starter John Lackey, who missed all of 2012 while recovering from Tommy John, is now enjoying possibly his best season ever.

That's not to say Harvey, assuming he ultimately goes under the knife, is guaranteed success when he returns. The severity of his tear will determine how long, and how grueling, his path back to the majors will be.