Geno Smith is out for the year, the New York Jets fourth-year quarterback done with an ACL tear suffered this past Sunday in a win over the Baltimore Ravens. But his comeback will be anything but easy.

Dr. Joshua Dines, sports medicine surgeon at Hospital for Special Surgery, tells Metro New York that Smith faces anything but an easy road back to the NFL. While the doctor hasn’t treated Smith, he is one of the nation’s premier sports medicine surgeons who is well familiar with the procedure. As such he outlines the outlook for Smith’s return.

Based on typical results, the Jets quarterback will be on crutches for at least several weeks and will also wear a brace. He will potentially be in a brace for at least six weeks and can potentially start running just a couple of months after the surgery.

“The reason why it is such a long recovery is because to reconstruct the ACL, a tendon graft from somewhere else in the knee is used,” Dr. Dines tells Metro. “The body then has to turn that tendon into a ligament. It is this biologic - or ‘ligamentization’ - process that takes time. “

Dr. Dines was listed as part of Castle Connolly’s Top Doctors in America and he has been the team doctor for the United States squad in the Davis Cup.

Calling the ACL “one of the main stabilizing ligaments in the knee,” Dr. Dines notes that unlike other surgeries, this one is particularly tricky. An ACL must be reconstructed, not just repaired.

A graft using one’s own tissues to reconstruct the ACL makes this a complicated procedure.

But given the importance of the ACL to an athlete, an easy return to the playing field isn’t easy. Same with getting back to an athlete’s previous high level of play, which could potentially take years.

“Despite the fact that most players will be back playing football by about a year after the injury, in many cases, it takes a few years before they return to their previous level of play. And, despite making it back to the NFL, their careers are typically shorter than age and position-matched controls,” Dr. Dines said. “Performance scores are usually lower after ACL reconstruction as well. In the case of Geno Smith, one thing he has going for him is that he plays QB. Quarterbacks have a slightly higher return to play rate than other football players. In one study, 12 out of 13 NFL quarterbacks returned to play in the NFL. Average career length after ACL reconstruction in this group was almost five years and their performance was very good.”