For most of the season Penn State's offensive line has stood as a nearly impenetrable wall. The line, which boasts four sack-free games to its credit, more often than not provided quarterback Daryll Clark with ample time to scan defenses.

But almost immediately when the Nittany Lions took the field at Iowa, Clark's normally secure pocket was breached by rushing Hawkeye defensive linemen. Clark was pressured for two hurries and a sack on the game's first three snaps, and didn't have time to try to find open receivers.

The wall had been broken.

Iowa defensive coordinator Norm Parker schemed his defense to take advantage of defensive tackles Mitch King and Matt Kroul on the inside. While the two all-Big Ten tackles tied up Penn State's interior linemen and forced them outside, the Hawkeye defensive ends looped behind them in stunts and attacked the open holes along the line.

For the first time this season, a defense attacked the middle of the Lion line and confused Penn State. Lion coach Joe Paterno said Iowa had success early because Penn State wasn't accustomed to the different looks the Hawkeye defensive front presented.

"They put a twist in there and we didn't quite pick it up, up front. They beat us a couple times up front," Paterno said. "They knew what they were doing; they played some formations, and they reacted well to the ball."

The Lion line adjusted to the look and didn't allow a sack during the rest of the game. But it did surrender season highs in both hurries (seven) and tackles for loss (seven).

Penn State running back Evan Royster, who was tackled six times for no gain or losses against Iowa, said while the Hawkeyes' stunting gave the Lions trouble, it was also a lack of execution on Penn State's part.

"They did do some stunting on the interior line," Royster said. "It was just a couple people missed a couple assignments on a play now and then."

With an Indiana defense that averages more sacks (2.6 per game) and tackles for loss (6.27 per game) than Iowa, the Lion offensive line will have to correct the problems that plagued it in Iowa City.

But unlike Iowa, Indiana gets most of its pressure from its ends rushing off the edge. Hoosier defensive end Jammie Kirlew leads the Big Ten with 18.5 tackles for loss on the season.

While Indiana's defensive front plays a different style than the interior-focused Hawkeyes, center A.Q. Shipley said after watching the tape from the Iowa game, the offensive line discovered its mistakes and should be more prepared if and when more defensive lines try to stunt against them.

"They gave us some problems in the passing game early on and we had to try and combat that," Shipley said. "We looked at the film and did everything we could to get everything corrected."