Mattison enters training camp in a backup role after Dalvin Cook decided against a holdout, the Vikings' official website reports.
Mattison was a frequent subject of fantasy hype in June and July when Dalvin Cook announced his holdout from team activities. The fourth-year pro ended up reporting for training camp, but Mattison is still one of the more valuable backups in the league, given the nature of Minnesota's offense as well as the reality that Cook has missed multiple games in each of his three NFL seasons. Of course, the Vikings also have Mike Boone and passing-down specialist Ameer Abdullah on their roster, so there's no guarantee of Mattison taking on Cook-like workloads in the event of a Cook injury.