Mattison was a non-participant in Wednesday's practice due to an ankle injury.
Mattison is banged up after handling one of his larger workloads of the season in the Week 14 win over the Lions. While the Vikings eased up on Dalvin Cook's usage while he managed a chest issue, Mattison stepped up for 46 yards on 14 carries and 18 more yards on two receptions. Despite being held out of practice to begin the week, the rookie told Chris Tomasson of the St. Paul Pioneer Press on Wednesday that he fully expects to suit up this weekend against the Chargers and is merely taking his recovery from the ankle injury "day by day."