What is Rob Gronkowski's shelf life?

Rob Gronkowski is to have back surgery in June, and he has had four forearm surgeries since November. AP Photo/Elise Amendola

In June 2012, the New England Patriots signed Rob Gronkowski to a six-year, $53 million extension. The move made sense at the time for the former AFC champs, because Gronkowski was coming off a record-setting year with 90 receptions, 1,327 yards and 17 touchdowns. Therefore, the Patriots didn't hesitate to sign him to the richest contract for a tight end in NFL history.

But just one year later, it's time to question whether the Patriots eventually will have buyer's remorse. There no denying his Hall of Fame talent, but Gronkowski also comes with durability issues.

How long will he last with the Patriots? Can Gronkowski be the same effective player in New England for five more seasons?

Gronkowski's injury history is no surprise. It started when he missed his senior year in college after major back surgery. As a result, the Patriots were able to get a first-round talent in the second round. But Gronkowski is going in for another back surgery in June, and it will mark his sixth surgery since February 2012. He has had four surgeries alone on his broken forearm since November.

Gronkowski has become a human pin cushion before his 25th birthday and has earned the dreaded label of injury-prone player. According to ESPN NFL analyst Matt Williamson, Gronkowski's growing list of injures "has to be a concern now."

"You hope that it's manageable," Williamson said. "The Patriots' doctors must have approved [Gronkowski's health]. There's no way you give him a six-year extension if they didn't think they were on top of the situation. But where we are sitting right now, it looks bad, doesn't it?"

Gronkowski's back surgery is described as minor by agent Drew Rosenhaus. However, former offensive lineman and NFL analyst Mark Schlereth provided chilling commentary from his experience with back surgery on ESPN's "NFL Live" this week.

Schlereth is an expert on going under the knife. He had 29 surgeries in his 12-year career, and he says recovering from a bad back is the worst of the group.

“Robert Watkins, the doctor who will perform [Gronkowski’s] surgery, is also the doctor who performed my back surgery. One thing you have to understand about back surgery, that area is so fine back there and scar tissue is a real issue and can irritate those nerve roots,” Schlereth said. “You sneeze and it’s over. Your back will just lock up on you. It’s one of those things that’s a really hard injury to have. And I’ve always said this: I’ve had 20 knee surgeries during the course of my career, and I would take another 20 knee surgeries to get the one back surgery back if I could get rid of it, because it bothers me every single day of my life.”

Gronkowski will miss a portion of training camp recovering from back and arm surgeries, and any setback could push his recovery into the regular season. He was in and out of the lineup all last season. He missed five regular-season games and the AFC Championship Game, which New England lost to the eventual Super Bowl champion Baltimore Ravens 28-13.

Can the Patriots win a Super Bowl this season without a healthy Gronkowski? Statistics show New England's chances are slim without its most effective pass-catcher.

According to ESPN Stats & Information, Patriots quarterback Tom Brady's Total Quarterback Rating is 77.3 since 2011 with Gronkowski on the field and 63.5 without Gronkowski. In addition, Brady averaged 10.5 yards per attempt over that same span throwing to Gronkowski, along with 31 touchdowns and four interceptions. Brady averages just 7.8 yards per attempt with 22 interceptions throwing to other receivers and tight ends. Gronkowski’s impact in New England is simply unmatched.

The Patriots need Gronkowski more than ever this season. They let go of 2012 starting receivers Wes Welker and Brandon Lloyd, who accounted for 192 receptions, 2,265 yards and 10 touchdowns last season. New England completely remade the receiving corps with less-proven veterans Danny Amendola, Michael Jenkins, Donald Jones, Lavelle Hawkins and rookies Aaron Dobson and Josh Boyce.

"It would be a huge blow, no doubt about it," Williamson said if Gronkowski misses time this season. "Even if Amendola makes up for Welker, which I have some doubts about, you got to think they will be weaker at receiver. I love the offensive line, and I think the running game is strong. [Tight end Aaron] Hernandez also is a good player. But Gronk is a difference-maker."

Contractually, the Patriots have a major decision to make with Gronkowski in 2015. New England has a $10 million option bonus that must be picked up by the final day of the 2015 league year. If the Patriots decide not to do that, the contract would be voided.

Gronkowski could be the best tight end of this generation if he ever finds a way to avoid injuries. But at this point it could be a challenge for Gronkowski, 24, to remain healthy and productive in the NFL at age 30.

"He could be the best tight end ever," Williamson said of Gronkowski's potential. "What he’s done in a short amount of time is unprecedented. He’s the best red zone threat in the league. He’s by far the best tight end in the league. He’s an elite blocker. He can run every route and is extremely physical after the catch. He can go up and get the ball in traffic.

"He has no flaws, except for durability."