Scheelhaase left Saturday's game against Western Michigan late in the third quarter due to an ankle injury. Beckman wouldn't go into detail about the injury and described it as "not a high ankle sprain, but it's dealing with his ankle."
Scheelhaase, a three-year starter, was 11 of 18 for 126 yards, a touchdown and an interception in the 24-7 win over Western Michigan. He also rushed for 21 yards and one touchdown.
"He practiced on Sunday night," Beckman said. "He was out there, definitely not full-go. I know Nathan is going to do whatever he can to be out there on Saturday. I'm a firm believer in practice. You got to go through some practice, at least Wednesday's practice. I've found out when you're not ready and prepared come Saturday... if you haven't practiced, you're going to have a hard time to perform on Saturday. We're going to see how that thing progresses. I just got done seeing him. He's looking better and better, so we're at least smiling.
"I want him healthy. We're going to make that decision based on what's best for him and the team. Does he have to be 100 percent? He has to be healthy to be successful and do what we're trying to do."
Sophomore quarterback Reilly O'Toole replaced Scheelhaase against Western Michigan. O'Toole was 2 of 3 for seven yards. As a freshman, O'Toole was 40 of 67 for 240 yards, one touchdown and four interceptions.
Beckman said he felt comfortable turning to O'Toole or junior Miles Osei if Scheelhaase can't play on Saturday.
"Rather than single them out (in practice), we're not, 'the one's get six reps and the two's get two,' " Beckman said. "We do the same exact thing. Reilly has gotten just about as many reps, so has Miles. Both of those two young men are going to be prepared this week to play in this football game. We'll see how they do and how they progress. Game plan, all that stuff, that will be very little change."
Illinois defeated Arizona State 17-14 in Champaign, Ill., last season. Scheelhaase was 11 of 15 for 135 yards, a touchdown and an interception and rushed for a team-high 67 yards. Both teams enter this season's game having won their openers.