That reason stands 6-2, weighs 235 pounds and commands the team's "Spread HD" offense. His name is Daryll Clark, and he is one of the lone new faces on the Nittany Lion offense this season.
After seeing limited time as a junior, Clark has taken hold of the team's starting reins and has been perfect from a record standpoint in guiding PSU to an 8-0 record and the No. 3 ranking in the country. Along the way, he has completed 114 of 180 passes for 1,531 yards and 11 touchdowns and has carried the ball 47 times for 190 yards and 8 touchdowns.
Offensively, though, it appears Clark is the primary defense between this year's high-powered team and last year's occasionally mundane PSU offense.
"He's pretty much turned their whole program around," OSU senior cornerback Malcolm Jenkins said. "He's brought a new swagger to the offense. His leadership is evident and he's all around the field making plays. It's definitely a step up from what they had last year."
Last year, it was Anthony Morelli running the show and the Nittany Lions scored a total of 289 points en route to a 9-4 record. Through the first eight games this season, the Clark-led PSU offense has amassed 363 points.
A native of Youngstown, Ohio, Clark received limited interest from the Buckeyes while prepping at Ursuline. He wound up enrolling at a prep school until he achieved a qualifying ACT score to get into PSU.
His phone has been ringing off the hook this week with friends from back home as he prepares to face the Buckeyes, he said.
"Ohio State really wasn't interested and they didn't really recruit me hard like Penn State did," Clark said. "One of the reasons was because of the grades. Coach Jim Tressel felt that he didn't want to take a risk on me, and they had Troy Smith there."
Although the Buckeyes did not heavily recruit Clark, they did scheme for him last year as they prepared to face the Nittany Lions in week nine.
"He's a guy that we were aware of last year and the year before that even knowing they might put him in for a few series," OSU senior linebacker James Laurinaitis said. "He's a guy we know has a lot of talent running the ball and you see how patient he is as a thrower as well. He's a good overall quarterback."
He was not a good enough overall quarterback, however, to unseat Morelli last season as a starter last season. The outgoing senior started all 13 games, but Clark did see action throughout the season.
The highlight came in the Alamo Bowl, when Clark relieved Morelli as his team trailed 14-0 in the first quarter. He then threw a touchdown and rushed for another, helping tie the game, and then led a scoring drive that ended with a field goal and put the Nittany Lions ahead in a game they would eventually win 24-17.
He finished the game averaging 8.3 yards per rush on six carries and did not complete a pass. For the year, he was just 8 of 9 for 31 yards as a passer. Against the Buckeyes, Clark was 4-of-5 passing for 13 yards and did not have a rushing attempt.
Those passing abilities have improved this season.
"He's very patient and he's very comfortable in the pocket," Laurinaitis said. "He doesn't just look one way and throw; he scans the whole field. He's a very polished quarterback. Mix that in with his ability to run and he's dangerous."
OSU defensive coordinator Jim Heacock described Clark as being locked in right now from a passing standpoint.
"He's on target right now," Heacock said. "From what I see, he's on target. He's getting it to the right receiver and the ball is on the money. You very seldom see a bad throw."
OSU's coaches and players alike have pointed to the fact that Clark is a dual-threat quarterback as one of the chief reasons for the team's offensive turnaround. Keeping him contained in the pocket is the primary responsibility for the Buckeye defensive line.
"As long as everybody executes their responsibilities to the best of their abilities, it's easy to stop anybody," OSU senior defensive tackle Nader Abdallah said. "A guy like him, he's a mobile quarterback so if he has to be contained, he has to be contained. We have to flush him out and be able to get him down with great tackling. We just have to be able to be very versatile and we can't afford to have any mental mistakes."