Defensive end Henry Anderson, who has started 16 consecutive games for Stanford, will miss this week's game against No. 23 Arizona State and a few games after that because of a left knee injury.
Stanford coach David Shaw said Tuesday he was not yet certain how many games Anderson will miss, but he expects Anderson to return before the season is over.
Anderson, who had 5.5 sacks and 13.0 tackles for loss last season, has two tackles and half a sack this season.
No. 5 Stanford has an excellent backup at the position in Josh Mauro, who has one of Stanford's three sacks this season and had 5.0 sacks as a backup last year.