Mattison (ankle) did not participate in Thursday's practice.
Mattison said Wednesday that he'll play in Sunday's game against the Chargers, but back-to-back absences from practice cast doubt on his assertion. Should the rookie ultimately land on the Week 15 inactive list, Dalvin Cook might see even more work than usual during Sunday's game against the Chargers. Alternatively, the Vikings could give Mattison's vacated snaps to reserve running backs Ameer Abdullah and Mike Boone.