Minnesota Vikings quarterback Sam Bradford suffered a knee injury that required an MRI this week and also kept him to limited participation in practice Wednesday and Thursday.
On Friday, Chris Mortensen of ESPN (via Adam Schefter) reported the Vikings are concerned about the ailment but still have "guarded optimism" about his status for Sunday's Week 2 game against the Pittsburgh Steelers.
Durability has long been a concern with the Oklahoma product considering he played 10 games in 2011 and seven games in 2013. He also missed the entire 2014 campaign with a torn ACL.