The veteran left tackle, who had put his knees and shoulders through multiple surgeries since a devastating 2002 pelvic injury, signed a three-year contract in March 2010 to return to the Green Bay Packers for an 11th year. He said once his body was no longer holding up, he'd know when to step aside.
He never envisioned, however, facing that potential reality less than two games into his new deal.
Yet, here he was, week two at Lambeau Field against Buffalo, and one of his troublesome knees was acting up. He could neither anchor his body properly in pass protection nor drive his legs as a run-blocker. As a result, he was struggling against Bills defensive end Dwan Edwards, he of three sacks in six NFL seasons.
The coaches yanked Clifton from the game with six minutes left in the second quarter in favor of rookie first-round draft pick Bryan Bulaga. The Packers won the game handily without Clifton to improve to 2-0, but his performance against Edwards begged this question: How would he fare the following week against Chicago's Julius Peppers? Other premier pass-rushers, such as Dallas' DeMarcus Ware awaited.
Headlines blared that the transition to Bulaga as quarterback Aaron Rodgers' blindside protector had begun, and that Clifton had become little more than an expensive insurance policy.
A quiet big man who's never been comfortable with excessive attention, Clifton, as usual, wasn't talking, but plenty were talking about him.
"I never paid too much attention to that sort of thing," Clifton told packers.com in a recent interview. "But yeah, you do hear it. You hear it from family, friends and things like that. I had to trust in my skills and our training staff."
As it turned out, his faith was well-placed.
Not only did Clifton not miss a start in 20 games, including the postseason, but he enjoyed probably his best year as a pro. A starter since midway through his rookie season in 2000, when he came to Green Bay as a second-round draft choice, Clifton was voted to the NFC Pro Bowl squad for the first time in his career (he made the Pro Bowl roster once before, as an injury replacement in 2007). His work against a murderer's row of pass-rushers during the Packers' six-game run to the Super Bowl title was as impressive as it was vital to the team's success.
So how did his prospects for the season change so dramatically from mid-September?
In his typically guarded fashion, Clifton didn't share many specifics about the treatment for his knee, but he praised team physician Dr. Pat McKenzie and the training staff. They devised a rehab regimen that calmed the early-season irritation and helped him manage his pain over the long haul.
"I think the older you get, the more you have to do as far as rehab, pre-hab and things in general in the weight room," Clifton said. "I just focused on really specific exercises to strengthen the hip, strengthen the quads, hamstrings, everything around the knee that supports it. That's what I've had to do for quite a while now."
He also credited Head Coach Mike McCarthy for adjusting his practice schedule to reduce the overall wear and tear. Clifton has practiced on a somewhat modified schedule for years, but when the knee problems cropped up so quickly this time, it was altered again.
Most weeks, he participated only in the opening jog-through portions of non-padded practices on Wednesdays and Fridays, and he took a more complete set of snaps during the padded Thursday workouts.
As the season progressed, the weekly questions asking whether Clifton – who was ultra-reliable in missing just two of 101 games from 2003-08 following the pelvic injury – would play, diminished. Privately, Clifton felt confident following the week-four contest vs. Detroit that he'd finish the season.
How he would perform also became a given again. More than once McCarthy stated publicly that Clifton had never played better during the head coach's five years.
"I certainly appreciate those comments and, yeah, I would agree," Clifton said. "I had some games this year where it was probably the best football I've played."
The stretch run became his time to shine.
Beginning with the week 16 game vs. the Giants, Clifton faced New York's Osi Umenyiora, Peppers twice, Philadelphia's Trent Cole, Atlanta's John Abraham and Pittsburgh's James Harrison, a quintet that has combined for eight first-team All-Pro selections, 18 Pro Bowls and 21 double-digit sack seasons.
Collectively, they tallied just two sacks against Clifton during the Packers' six-game march to immortality.
"Those are definitely some good football payers, no doubt about it," Clifton said. "I kind of knew going into that stretch that if we wanted to reach our ultimate goal, that each and every week it's going to be an outstanding defensive end or linebacker that I'm facing.
"You just have to prepare mentally, trust in your techniques. With me not maybe getting as many practice reps as some of the other guys, you really have to do your film study, and you just have to know your opponent."
Clifton also knows his body, so when he says that this is as good as he's felt physically "in a number of years" after a season, even a 20-gamer, there's no reason to doubt him. General Manager Ted Thompson expressed his desire at the scouting combine for Clifton to remain the starting left tackle for the time being.
As for anything beyond 2011, Clifton is sticking to what he's always said about his body holding up and knowing when it's out of gas.
It isn't yet. It wasn't last September, either, despite indications to the contrary.
Now he has time before he has to ponder those words again.
"That's why you have the offseason to heal up," Clifton said. "It's getting your body right. It's getting ready for the grind, and then you have the preseason and you start preparing for a 16-game … maybe another 20-game season.
"Or 19. Hopefully we'll get a bye in there."
Mike Spofford is a 1995 Masters graduate of the Medill School of Journalism at Northwestern University who worked as a sports reporter for two daily newspapers in Wisconsin. Spofford has been a packers.com staff writer since 2006.