Vikings quarterback Tarvaris Jackson has been diagnosed with a sprained MCL in his knee, a league source tells us.

Jackson injured the knee while being tackled during Saturday night’s game against the Ravens.

He is expected to be able to return for the team’s final preseason game.  Already, he’s riding a stationary bike at the team’s facility.

Jackson was 8-4 a year ago as a starter.  With defenses focused on running backs Adrian Peterson and Chester Taylor, Jackson will be expected to get the ball to open receivers this year.