Source: Mariota played Stanford with partial sprain of MCL

Source: Mariota played Stanford with partial sprain of MCL »Play Video
Oregon quarterback Marcus Mariota (8) passes as Stanford linebacker Shayne Skov (11) defends during the first quarter of of an NCAA college football game in Stanford, Calif., Thursday, Nov. 7, 2013. (AP Photo/Marcio Jose Sanchez)

EUGENE, Ore. -- Marcus Mariota has been wearing a knee brace on his left knee, and a source with knowledge of the situation told KVAL Sports that the Ducks quarterback has a partial sprain of his MCL.

Mariota took the field in Thursday night's game against the Stanford Cardinal wearing a knee brace on his left leg. A source close to the situation told Harmon that the Ducks’ Sophomore quarterback is wearing the brace for a partial sprain of his MCL.

Earlier in the day the Oregon Athletic Department said that Mariota will take the field in healthy playing condition.

Mariota has thrown for 20 touchdowns and rushed 9 more this season, without a single interception.

In the latest Heisman polls, Mariota leads Florida State's Jameis Winston and last year's winner Texas A&M's Johnny Manziel.