Joe Paterno underwent surgery Sunday, and though expected to fully recover, he won't be able to sustain weight on his left leg for an estimated six weeks, according to team doctor Wayne Sebastianelli.

It is unknown whether Paterno will appear on the sidelines or in the coach's booth for this weekend's Temple game, but that decision is expected to be made later this week.

Despite the setback, friend and director of branding and communications Guido D'Elia said Paterno was in high spirits yesterday.

"He's cantankerous as usual," D'Elia said, jokingly. "I'm amazed at [his toughness] but not surprised."

Several screws were inserted in Paterno's leg during the surgery at Mount Nittany Medical Center, and he was fitted with a temporary brace after suffering a tibial plateau fracture and tearing the medial collateral ligament (MCL) and posterior cruciate ligament (PCL) in his left knee. Paterno suffered the injury early in the third quarter of Saturday's game and was carted off the sidelines around the 2-minute mark.

"At some point, he was telling the doctors, 'Just get me home. I'll be all right,' " D'Elia said. "And they said, 'We're going to have to do some [tests].' He looked at them, 'Well, why?' Like he was bruised or something -- that's just the way he is."

Andrew Quarless, the tight end who collided with Paterno's right leg, approached the coach to check how he was doing. When he asked, Quarless got an earful from Paterno -- "Keep your head in the game," the coach instructed.

Paterno, a fixture on the Penn State sidelines for the last 56 years, has been getting around via golf cart. Defensive coordinator Tom Bradley, who took the reins after Paterno went down, joked on Saturday that practices might work a little differently now.

"He'll probably wear a red cross like everybody else for a couple days, then a green cross, and he'll be ready to play," Bradley said, smiling. "I don't question that he'll be all right."

Paterno's injury as head coach of a football team is rare -- but not unprecedented. Former Wisconsin coach Barry Alvarez was in a similar situation in 1999 when he was 52 years old.

Alvarez, who suffered from a chronically sore right knee, stumbled while walking down a ramp during a game in early September. He was forced to make several visits to the hospital (he needed a knee replacement, but the knee was infected), miss a few games and sit in the coach's booth for the remainder of the season.

Still, Alvarez played a huge role off the field and helped lead the Badgers to a Rose Bowl that season. Alvarez coached another five years and won another four bowl games before retiring.

Paterno may have about 20 years on Alvarez, but D'Elia said the Nittany Lions' head coach is healthier than most.

"You might have friends or relatives that age, but this isn't a typical person. This is not your 79-year-old uncle," he said. "I'm starting to no longer be surprised by the way he's able to handle things physically."