The news was first reported by The Oregonian.
Herbert, a sophomore, had completed seven of eight passes for 86 yards and a touchdown before the injury. He left after a 7-yard touchdown run.
Herbert had been impressive in leading the Ducks to a 4-1 record this season. He had a completion percentage of 68.3, 1,264 passing yards nine touchdown passes and three rushing touchdowns.
The Ducks brought in senior QB Taylor Alie to replace Herbert, but Alie was knocked out of the game in the fourth quarter with an injury of his own.
Oregon freshman Braxton Burmeister, who had been expected to redshirt, came in to make his season debut.
Oregon hosts No. 16 Washington State, which is coming off a 30-27 victory over No. 5 USC on Friday night in Pullman on Saturday.