WEST LAFAYETTE, Ind. -- No. 6 Penn State put a hurting on Purdue yesterday to remain perfect.

The Nittany Lions' 20-6 victory briefly helped take coach Joe Paterno's mind off his own pain.

Paterno, two months shy of his 82nd birthday, was forced to return to the coaches' box for an entire game for the first time since the 2006 Outback Bowl after pain flared up in his sore right leg.

Paterno was injured three days prior to the Aug. 30 season opener while attempting an onside kick in practice.

It has gotten progressively worse.

He wore two different shoes to his postgame news conference and used the podium to help support himself while answering questions.

Paterno, who also worked the second half of the Temple game from the coaches' box a few weeks ago, was asked if his leg injury would require surgery.

"I don't know yet," he said. "It's not my knee. The knee is fine. When I was horsing around ... I overdid it with this one, so I got a little arthritis. ... But I'm not letting anybody get near me with a knife."

Paterno, whose left leg was injured in a sideline collision with a Wisconsin player two years ago, admitted this is the first time in his 43 seasons as coach that his health has become a weekly issue.

"That's why I'm reluctant to really get into what's going to happen next week," he said. "... Some days, [my leg] doesn't bother me much at all. I get a little pain in it, but it doesn't bother me a lot.

"I've taken more pills in the last two months than I've taken in all my life. When I was a kid and something ached, my mom threw me in the tub, put steaming water in there, got out the olive oil and rubbed it on my head."

After his 10-minute news conference, Paterno -- the winningest coach in Division I history with 378 wins -- gingerly walked down a few steps. He got into a van, which transported him to a nearby airport for the charter flight home with the team.

"He's doing what he has to do to coach," Penn State athletic director Tim Curley said. "I don't know whether or not [his leg] is going to be a problem the rest of the year."

Jay Paterno, the coach's son and the team's quarterbacks coach, expects his dad to bounce back.

"It's tough," Jay Paterno said. "But he's going to be all right. ... He's out there every day at practice. He's involved in the game planning. He was very involved today with a lot of things we did. So I don't know that I'd be concerned about it. It's going to be week-to-week."

He jokingly said the only way his dad would get near a knife is if "my mom is cooking spaghetti or cutting up pasta or something."

Some of Paterno's players are worried about their coach's health heading into Saturday's showdown against Wisconsin at Madison, Wis., where Paterno was injured in November 2006.

Two weeks ago, Paterno was a rare no-show at a Monday practice.

"We're definitely worried about him," Royster said. "We like him on the sideline with us. He gives us a whole new sense of confidence when he's there."

"He's a great guy," wide receiver Deon Butler said. "He's our coach. Everybody feels dearly for him. We all hope he gets better. But when you get to the age he is, you've got to take it easy."

Penn State (6-0, 2-0 Big Ten) overcame a slow start to beat Purdue (2-3, 0-1).

Quarterback Daryll Clark scored on a 1-yard sneak midway through the second quarter and Kevin Kelly kicked a 25-yard field goal to give the Lions a 10-0 halftime lead.

Tailback Evan Royster scored on a 4-yard run in the third quarter and Kelly added his second field goal, a 20-yarder, in the fourth to close out Penn State's scoring.

The Lions finished with 422 total yards and Royster had his fourth 100-yard game of the year, finishing with 141 yards on 18 carries. Clark completed 18 of 26 passes for 220 yards. He was sacked twice.

Wide receiver Jordan Norwood missed his second consecutive game with a hamstring injury and Andrew Quarless made his first start of the year in place of Mickey Shuler, who re-aggravated a left ankle injury.

Purdue, which lost its 16th consecutive game to a ranked opponent, averted the shutout when tailback Kory Sheets scored with 6:28 remaining in the game.

Much-maligned middle linebacker Josh Hull had a career-high 11 tackles for the Lions, including nine in the first half. Nickel back Drew Astorino added an interception as the defense held Purdue quarterback Curtis Painter to just 112 yards passing and 241 yards offense before he was lifted early in the fourth quarter.