Co-offensive coordinator Chris Beatty said last week that the Illini had no plans to play more than one quarterback in the season opener against Western Michigan.

Those plans changed when starter Nathan Scheelhaase went down with an ankle injury in the third quarter.

Sophomore Reilly O’Toole replaced Scheelhaase, who, after being looked at by trainers on the sideline, was carted off the field.

“We’ll continue to evaluate it,” head coach Tim Beckman said after the 24-7 victory. “But you all know Nathan Scheelhaase. Nathan Scheelhaase will do whatever he can to make sure he’s prepared and ready for next week.”

The junior quarterback appeared to injure his left ankle on a read-option play with about 10 minutes remaining in the third quarter. Western Michigan linebacker Kyle Lark landed on Scheelhaase’s left ankle, twisting it outward. Scheelhaase remained on the field for the remaining three plays of the drive, which ended on an interception in the end zone.

Beckman confirmed Monday that Scheelhaase did injure his ankle, but did not elaborate except to say that it wasn’t a high ankle sprain.

He said Scheelhaase was at practice Sunday but was “definitely not full go,” adding that he believes a player needs at least some practice — particularly Wednesday’s full practice — before playing in a game.

Prior to exiting the game, Scheelhaase was 11-for-18 passing for 126 yards with one touchdown and an interception, also adding a 4-yard rushing touchdown.

The offense was stagnant in Scheelhaase’s absence, while O’Toole was just 2-for-3 for 7 yards in his place.

“Reilly was kind of up and down,” Beckman said. “We’ve got to make sure that we’ve got him doing a little bit more of what we want to do instead of letting him make some of those checks.”

O’Toole said he noticed Scheelhaase limping a few plays prior to exiting the game and was prepared to take the field.

“Nate’s a reckless player,” O’Toole said. “He’ll lower his shoulder. Just the way he plays, he plays all out, plays every down like it’s his last. With that being said, you’ve got to be ready (as his backup) at any point in the game.”

While Scheelhaase is a more accomplished rusher — he led the team in rushing yards last season with 624 — Beckman said the offensive game plan won’t change much if O’Toole is the starter.

“We believe in what we’re doing offensively,” Beckman said. “We’ll still run the same stuff that we were running with Nathan. Coach Beatty does a great job with the quarterbacks and has them prepared.”

O’Toole runs with the second-team offense in practice, but said he receives the same number of reps and runs the same plays as Scheelhaase with the first team.

Versatile third-string quarterback Miles Osei also saw action in Saturday’s win but didn’t attempt a pass. Beckman said Osei will see more time this week, if not at quarterback then at wide receiver or running back.

Beatty said he’s comfortable going into Tempe, Ariz., with O’Toole and Osei in the event Scheelhaase can’t go against Arizona State on Saturday.

“I feel like those guys can win games in this league,” Beatty said. “We’ll get those guys ready if we have to.”

_Chad can be reached at [email protected] and @cthornburg10._