Minnesota defensive tackle Kevin Williams has a hyperextended right knee but no ligament damage after a low hit the Vikings felt was illegal.
Coach Leslie Frazier said Monday that an MRI on Williams also revealed a "significant" bone bruise as well as a strained posterior capsule, the thick structure that surrounds the knee.
Williams was hurt Sunday at San Francisco when 49ers guard Joe Looney took him down with a chop block away from the play in the third quarter. Williams didn't see the hit coming, and Frazier said after the game the team would probably send video to the NFL for possible punishment.
The Vikings have been planning to rotate Williams and rookie Sharrif Floyd this season. Floyd is recovering from a minor left knee injury.