NFL insider Ian Rapoport‏ has bad news for Vikings fans.

He is reporting that rookie RB Dalvin Cook who left the game with an apparent knee injury does, in fact, have a very serious leg injury.

Rapoport tweeted earlier that Cook has "a nearly complete ACL tear." Tom Pelissero reported on Twitter that Cook left the Vikings locker room "on crutches, knee in a brace."

Any ACL tear would likely mean the end of the season for the rookie.

**UPDATED**  Minnesota Vikings Confirm That RB Dalvin Cook’s Season is Done