India, Sept. 17 -- The Minnesota Vikings are set to begin the early portion of the season without their primary running back as the team deals with another setback on offense.

Head coach Kevin O'Connell announced Wednesday that Jordan Mason will be placed on injured reserve after suffering a fractured thumb. Mason underwent surgery to repair the injury and is expected to miss at least four games.

Because Minnesota has its bye in Week 6, the timing of the injury could give Mason roughly five weeks to recover.

If his rehabilitation progresses as expected, the 27-year-old would be eligible to return for the Vikings' Week 7 matchup against the Indianapolis Colts at U.S. Bank Stadium.

Mason opened the season as Minnesota's leading rusher a...