Despite advances in the medical field, recent history does not provide a comparable example of a player near the age of 34-year-old Adrian Wilson—who was signed Monday by the Chicago Bears—returning from a torn Achilles tendon to re-establish himself as an impact player.
In fact, just one player who has suffered the injury at age 32 or older in the last 10 years has come back to start at least 12 games the next season.
Wilson, who turns 35 in October, tore his Achilles in late August of last year. He spent the entirety of the 2013 season on injured reserve, and the New England Patriots eventually released the five-time Pro Bowler in early April.
His wait for another chance ended this past week, when the Bears gave Wilson what can only be described as a low-risk opportunity to show he has something left in the tank. According to Adam Caplan of ESPN, Wilson's deal is for one year and the minimum $955,000, of which zero is guaranteed.
The Bears have simply bought themselves a few months to find out how Wilson moves post-injury, and how he stacks up against the rest of Chicago's rather underwhelming safety group. But expectations should be kept low.
The fact that Wilson was still available deep into June speaks volumes on how the NFL valued him. And his eventual contract showed that even the Bears are entirely unsure of whether Wilson can crack the 53-man roster.
Rehabilitation of Achilles tendon injuries have improved in recent years, with players such as Demaryius Thomas, Terrell Suggs, Jason Peters and Michael Crabtree returning to elite levels post-surgery. But that group consists of mostly younger players, and not one of the four is a safety.
"Science and rehab are more and more advanced every few years," an NFL personnel director told Tom Pelissero of USA Today. "Age, conditioning, body type come into play as well. The better those statuses are, the better chance of quality return."
It is telling that age was the first factor listed by the personnel director.
If Wilson returns at 34 years old to make an impact with the Bears, he'd be the first at his age to do so in the NFL in recent history.
Since 2002, no player age 32 or older at the time of the tear has returned to pre-injury levels. The best comparable is former New York Jets pass-rusher Bryan Thomas, who at 32 years old tore his Achilles tendon. He returned a year later, but he played in just 12 games and had only 2.5 sacks. It was his final season in the NFL.
Others, such as a 28-year-old Lavar Arrington, a 29-year-old Jamir Miller and a 31-year-old Earnest Graham, tore their Achilles and never played another down.
Going back to pre-2002 provides an even grimmer prognosis. Four orthopedists at Duke University published a study in the journal Lower Extremity Review in 2010 that concluded only 21 of the 31 players found to have torn their Achilles' tendon from 1997 to 2002 returned to play in the NFL. And in general, those players saw "significant" decreases in playing time and performance.
The study also found the average age of a player with the injury was roughly 29.
While no statistics were provided for individual positions, Wilson's placement at safety does matter in terms of the injury.
"For Wilson and anyone in the defensive backfield, it's about function," Bleacher Report's Will Carroll said in an email interview. "The Achilles makes so many things possible. Let's assume that walking and running are ok, but if he gets back his quickness, his ability to cut, his ability to react to the ball and the receiver, then he's back where he was. We're seeing Achilles repairs getting better and better, from Kobe Bryant to Terrell Suggs, so there's a chance. But there's going to be so much more stress on a defensive back that it's tough to imagine he won't leave something behind."
Playing safety requires a number of athletic abilities that could be severely compromised by an Achilles injury. The position is essentially built on making quick decisions upstairs and having the lower body react in harmony.
The Achilles' tendon connects the bones in the heel to the calf muscle. It is the strongest tendon in the body, and it is needed to push off the foot. Nearly every athletic movement—from running to jumping and everything between—requires a working, stable Achilles tendon.
Tearing the tendon can be devastating to the safety position. Just look at former Carolina Panthers safety Charles Godfrey, who signed a $27 million deal before 2013 but then had to take a paycut and accept a position switch after tearing his Achilles in Week 2 of last season.
Cornerback Brent Grimes did return to Pro Bowl levels after tearing his Achilles at age 29, but again, a five-year gap between Grimes and Wilson is significant.
Maybe the best hope for Wilson is the comeback of Greg Ellis, who tore his Achilles tendon at age 31. He returned a year later to tally 12.5 sacks over 13 games, earning the NFL's Comeback Player of the Year award and a Pro Bowl invitation. He stayed productive over his next two seasons, playing in 30 games and registering 15 sacks.
But Ellis was also two years younger than Wilson, and it could be argued that playing edge-rusher is easier following the injury than defensive back.
Comparing Wilson to an NBA player doesn't add much value to the conversation, but it is worth noting that Kobe Bryant tore his Achilles tendon at age 34. He returned eight months later, only to suffer an injury to his knee that kept him out the rest of the 2013-14 season. Even if Wilson returns, he faces the possibility of re-injury.
The Bears signed Wilson despite knowing most (if not all) of this information. And given their current safety situation, it's not difficult to understand why.
Ryan Mundy, M.D. Jennings, Chris Conte (who is injured), Danny McCray and Craig Steltz form an uninspiring group of veterans, and fourth-round pick Brock Vereen is still a green, untested rookie. Conte and Major Wright were a disaster in 2013, but the 2014 group has the potential to be porous, too.
Wilson is unlikely to solve the problem. But at the height of his powers, few safeties in the game were better, and his presence could both raise the competition level and give the Bears a veteran voice in the safety room during training camp. Anything more from Wilson would be a huge plus.
Given the money the Bears are investing in Wilson, there's no tangible reason to knock the move. It's no risk and all potential gain, even if the likelihood of Wilson providing a real impact in 2014 remains very small.
Zach Kruse covers the NFC North for Bleacher Report.