(Minneapolis, MN) -- NFL leading rusher Dalvin Cook is not expected to play on Sunday as he deals with an adductor strain. The Vikings' standout underwent an MRI earlier this week. He was hurt during the Week Five loss to Seattle. Cook's 489 rushing yards and seven TD's are both first in the league. Alexander Mattison is likely to start at running back for Minnesota, which sits at 1-and-4 and faces winless Atlanta on Sunday.