Cook sustained the injury during the second quarter while trying to make a tackle. The injury will sideline Cook for 7-8 weeks, and he will be placed on the injured reserve with a designation to return. This likely puts Cook out for the rest of the regular season, but leaves open the possibility of a return for the playoffs if the Vikings qualify.
The designation to return is new to NFL roster rules this year. Previously, a player was ineligible for the rest of the season if placed on the injured reserve, but now one player per team can return to the active roster after being on the injured reserve.
Cook is in his third year in the league, and has started all eight games for Minnesota this season after appearing in six games in each of his first two years. He has recorded 56 tackles and 11 passes defended in his 20 career games.