Cook (ankle) doesn't appear to be practicing Friday, as he left the field after stretching, Eric Smith of the Vikings' official site reports.
Cook played through the ankle sprain in last Sunday's loss to Arizona, but he wasn't his usual productive self after lighting up the Cardinals in the first half. He's now missing practice for a third straight day, potentially setting up a game-time decision ahead of Sunday's matchup with Seattle at 4:25 p.m. ET. If Cook were to miss the game, Alexander Mattison would figure to get the start at tailback, with Ameer Abdullah and/or A.J. Rose likely called up from the practice squad for backup work.