If there's one reason not to rule out Illinois -- a 17.5-point underdog in Vegas -- this weekend, it's because of one specific athlete.

True freshman Isiah "Juice" Williams.

He may be only one player, but his Michael Robinson-esque playing style has given the Fighting Illini offense a shot in the arm since he started Week Four -- a fact that's not lost on the Penn State defense.

"He's a great athlete. Whenever he has a chance to pull the ball down and run, he does," linebacker Sean Lee said. "When you play against an elusive quarterback like him, it's hard."

In his four starts this season, Williams has averaged 74 rushing yards. That running ability is a huge part of what makes him so dangerous; even Penn State's Mike-Rob only scampered for about 67 yards a game last year.

But if Williams has one Achilles' heel, it's accuracy. The rookie signal caller is completing less than 43 percent of his passes -- not good news when you're a quarterback.

Still, Illini wideout DaJuan Warren said his teammate is getting better.

"He's understanding on some of the throws, he doesn't have to throw as hard. Some need a little touch on them," he said. "He's worked on it, and his accuracy has improved."

That's shown the past three games. Williams still has more incompletions, but his 49.2 completion percentage is markedly better than before. Also, in those last three starts, Williams has upset a Michigan State squad and lost in the two other contests by a combined five points.

Illinois may not be a pushover anymore -- at least not with a four-star recruit who was invited to the 2005 EA Sports Elite 11 Quarterback camp. But, statistically, Penn State is the top pass defense he's had to start against.

Williams has gotten the nod against defenses ranked Nos. 61, 62, 74 and 97, respectively. The Nittany Lions are listed at No. 28, but those numbers didn't exactly put Dan Connor's mind at ease.

"He's definitely a threat," Connor said. "We've been watching a lot of film; he can make plays happen. But as far as the game plan, you can't get too far away from what you've been doing and what's been working so far."

In high school, teams had to completely restructure game plans against him. Williams ran almost as often as he passed -- he recorded 1,841 passing yards and 1,441 rushing yards.

Obviously, that type of production won't carry over to the collegiate level. But Williams' ability to make those big plays continues to be a problem for opposing teams.

He's only competed in seven games, garnering four starts, and he already broke Illinois career-passing record for most touchdowns over 65 yards -- with three. All but one of his eight touchdown scores this season have been longer than 31 yards, while those scoring drives haven't lasted longer than six plays and two minutes, 22 seconds.

"He's a dual threat quarterback, he can tuck it and run. That's the main thing we're worried about, him scrambling for yardage," Lee said. "The main thing that changes when he scrambles, receivers break from their routes -- that'll be big this week."