At his locker, he demonstrates. Alex Green takes a step and crouches into a squat — a simple, safe exercise for boys and girls.

Yet midway through last season, this was impossible. The Green Bay Packers running back couldn't perform one stinking, weightless squat on both feet.

"Just like that with no weights," Green said. "Nothing. I couldn't do that."

No, Green's return from a torn anterior cruciate ligament in his left knee did not follow Adrian Peterson's Hollywood narrative. Far from it. Whereas Peterson threatened the NFL rushing record, Green's 2012 season consisted of throbbing, miserable mornings, frustration on Sundays and an anticlimactic limp to the finish line.

Green "led" the Packers in rushing with 464 yards on 135 carries (3.4 avg.) with no touchdowns.

All along, Green wasn't himself. His knee never felt right.

So even with Green's future in Green Bay instantly endangered by the addition of a second-round pick (Eddie Lacy) and a fourth-rounder (Johnathan Franklin), he can breathe easy. His body, finally, responds to his brain.

Green Bay isn't kicking Green to the curb, either. Through the team's organized team activities and minicamp practices open to the media, the 2011 third-round pick started and finished as the No. 1 back.

No, it's not time to count out Alex Green quite yet. This summer — running, cutting, accelerating — he feels like himself again.

"It's kind of like...," Green said, "it is hard to explain, hard to explain. It's like if you got a bruise or something and at first, you can't really move your arm but over time it starts to loosen up and eventually you get back to where you were before."

Moments before taking off on the Packers' Tailgate Tour in May, Green said he was never 100% last season. But as he explained this week, that hardly scratches the surface. Green probably should have shut down long before mid-December.

Pain in the knee began in the middle of training camp and never subsided. After one game — Oct. 14 at Houston, Green recalled — the running back had to be carried a short distance by others to get treatment. After practices, he often hobbled up and down stairs on one leg. And before hitting the light to sleep, Green downed four, sometimes five Advils.

The 6-foot, 220-pounder slept in fear of the deep burn that would strike in the morning.

"I'd wake up and I was just in pain," Green said. "Taking pills and worrying how it can get better, but knowing it was getting weaker, it was frustrating."

He couldn't mask the pain on the field, either. Each cut on the left knee stung. Not ideal for a running back built for a zone-blocking scheme. Green braced for each cut, each plant of the cleat into the turf. He'd strap tape around his knee. He'd slip a sleeve over it. Green tried everything to fix this "loose, unstable" feeling in his knee.