The Vikings’ No. 3 running back, Boone was backing up Dalvin Cook — who was challenging for the NFL rushing lead — and Alexander Mattison, a breakout rookie.
But when Cook suffered a chest injury Nov. 17 in a victory over Denver, Boone’s practice runs became particularly aggressive. Vikings coach Mike Zimmer noticed Boone’s fresh legs setting a tempo as starters lost some energy thanks to the wear and tear of the first 11 weeks of the season.
If Boone stopped long enough to look around in practices this week, he’d see nobody in front of him in the Vikings backfield.