By Bill Bradley, contributing editor
Despite the remarkable recovery of Minnesota Vikings running back Adrian Peterson two years ago, not every player rehabbing from a knee injury will be back on the field in eight months.
NFL Network Health and Safety Chief Correspondent Andrea Kremer said while there is no cookie-cutter timetable for bouncing back from ACL injuries, some NFL players believe they are not 100 percent back from knee surgeries until as many as three seasons after the injury.
"Every body is different," Kremer said Thursday on "NFL Total Access." "Every knee heals differently. And every ACL injury is unique because there is different amounts of damage that has been sustained to the knee."
Last year, Kremer chronicled Darrelle Revis' comeback from a major knee injury. She noted that for many NFL players their knee is stronger the second season after the surgery.
"Revis made the Pro Bowl last year, but he'd be the first to tell you that it's this upcoming season that the 'Island' will be officially open for business," she said. "And there are equally high expectations for (Robert Griffin III) for this upcoming season."
Arizona Cardinals quarterback Carson Palmer, who came back from an ACL tear during a 2006 playoff game with the Cincinnati Bengals, said it's tough enough preparing for the season healthy.
"To add a surgery like that, it's just a long, long grind," Palmer said. "You go through so many different emotions and so many physical struggles."
Famed orthopedic surgeon Dr. James Andrews said the athlete may not always understand how severe the injury can be. He said it may take more than a year for some athletes to get the strength back in their quads alone.
A 2010 study found that one third of the players who suffered an ACL injury did not return to the NFL after the surgery. The ones who made it back needed an average of 11 months of recovery before playing again.
"I think the first season back is just scary," said Palmer, who thinks recovery can take as much as three seasons. "You're told that it will hold up and you're told that it's ready, but until you get onto the field, and get hit low a couple times ... until that happens, you don't really know that it is completely healed.
" ... I thought that I would get that same push-off, that same drive. The truth of the matter is, you'll never to get to exactly where that knee was before it was cut open and things were moved around."
Also, Kremer said studies show that there is a 5-6 percent chance of a recurrent injury to the same knee within two years.
