The Washington Redskins have confirmed that Robert Griffin III will need further tests to assess the damage to his knee.

The rookie quarterback underwent an MRI scan yesterday, after aggravating a sprain from earlier in the season during the Redskins' 24-14 loss to the Seattle Seahawks on Sunday.

Head coach Mike Shanahan told reporters: "Any time there's old injuries with ACL and lateral collateral ligament, there's always differences of opinion on the MRI, so that's why he's going to see [renowned orthopedic surgeon] Dr Andrews [today]."

The Redskins have described the results of the MRI as "open to interpretation".

Local media in Washington have reported that RG3's scan indicated partial tears to his ACL and LCL ligaments.