Buffalo Bills reserve defensive tackle Spencer Johnson has been ruled out from playing at San Francisco this weekend because of an ankle injury.

Coach Chan Gailey made the announcement after Johnson missed his second straight practice Thursday. Gailey said Johnson was hurt but continued playing in a 52-28 loss to New England on Sunday.

Gailey also said offensive linemen Cordy Glenn and Kraig Urbik are expected to miss at least two games after both hurt their right ankles last weekend. Both have already been ruled out from playing against the 49ers.

Rookie cornerback Ron Brooks has been working out for the past week since having a cast removed from his right foot. Brooks broke his foot in the preseason, and is eligible to be activated after Week 8.

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