WEST LAFAYETTE, Ind. — It just wasn't the same without Joe Paterno roaming the sideline.

Sure, Penn State's 81-year-old coach notched another victory today, this one a 20-6 win over Purdue. But he did it from the press box because a lingering right hip injury limited his mobility.

Paterno was hurt while performing an onside kick during practice on Aug. 28. Saturday's game marked the first time this season he didn't start a game on the sideline. He doesn't know if he'll coach from the press box next Saturday against Wisconsin.

"I'm reluctant to get into what's going to happen next week," he said. "I just think that some days, it doesn't bother me much at all. I've got a little pain."

Penn State's players noticed Paterno's absence during the game.

"It is different, but we don't want him to come down there if he's hurt," running back Evan Royster said. "We want him to be able to do the best for our team."

Paterno found the strength to be on the field at the end of the game so he could shake hands with Purdue coach Joe Tiller, a friend who will retire at the end of the season. But such things are a challenge, now that he also deals with arthritis.

"I've taken more pills in the last two months than I've taken all my life," Paterno said.

He prefers pills to the alternative.

"I'm not letting anybody get near me with a knife," he said.

Royster was one of the main reasons that Paterno's only worry was his hip. Royster ran for 141 yards and a touchdown and had 53 yards on four catches in No. 6 Penn State's win.

Daryll Clark completed 18 of 26 passes for 226 yards and ran for a score for Penn State (6-0, 2-0 Big Ten), which outgained Purdue 422 yards to 241.

Purdue quarterback Curtis Painter finished 13-for-22 for 112 yards. He moved past Mark Herrmann into second place on the school's career yards passing list, but on a day in which the 10,000 career yards passing milestone was in reach, he fell short and was benched in the fourth quarter. The loss left Painter with an 0-9 record against ranked teams in his career, and Tiller has lost 15 straight against ranked opponents.

Kory Sheets led Purdue (2-3, 0-1) with 59 rushing yards on 18 carries and 25 yards receiving. He broke a tie with Mike Alstott to set a school record with 40 career rushing touchdowns.

Purdue kicker Chris Summers missed a 45-yard field-goal attempt wide right on the first play of the second quarter to leave the game scoreless.

Penn State responded with the game's first scoring drive. Penn State running back Dan Lawlor was stopped on a third-and-goal from the 1, and Purdue appeared to have Penn State stopped on fourth down, Officials ruled that the fourth down play didn't count because the previous play was being reviewed. The original call that Lawlor was short of the goal line stood, but Purdue fans were upset that the team's key stop was taken away. On the fourth down play that counted, Clark scored on a quarterback sneak, and Penn State took a 7-0 lead.

Summers was wide left on a 36-yard field goal with 3:41 left in the second quarter. Penn State kept the ball for the rest of the half, and finished the second quarter with a 25-yard field goal by Kevin Kelly that increased the Nittany Lions' lead to 10-0 at halftime.

Royster scored on a 4-yard run with 8:02 left in the third quarter to make it 17-0.

Late in the third quarter, Penn State safety Drew Astorino intercepted Painter and returned it 29 yards to the Purdue 30. Kelly made another field goal early in the fourth quarter, to make it 20-0.

Joey Elliott replaced Painter and quickly led Purdue down the field. Elliott's fourth down completion to Desmond Tardy put the Boilermakers at the Penn State 1, and Sheets went over the top for Purdue's only points to make it 20-6.

Penn State ran out the clock after that, and Paterno earned his 378th career win.

Penn State receiver Derrick Williams said though the other coaches communicate well on the field, Paterno's presence is irreplaceable.

"It was very difficult," he said. "With Joe there, you're always alert about what's going on."

This wasn't the first time a health issue has slowed Paterno.

Paterno's left leg was broken and knee ligaments were torn in November 2006 when he was hit on the sideline during a game at Wisconsin. He was forced to miss a game and then had to coach the Outback Bowl in a coaching box above the field.

He also coached the second half of this season's win over Temple on Sept. 20 from the press box. He said he decides where he will coach the day of each game.

"I take some stuff," he said. "Some days I feel great, some days I don't. So I wasn't sure whether I was going to be on the field or coach upstairs. Today was a tough day."