Tarvaris Jackson injures knee

Posted by ESPN.com's James Walker

BALTIMORE, Md. -- The Minnesota Vikings received a scare Saturday night as starting quarterback Tarvaris Jackson injured his knee in the first quarter of their preseason game against the Baltimore Ravens.

Jackson was scrambling on the team's second offensive drive when he was hit coming up the right sideline. He ran one more play before limping and taking himself out of the game.

The severity of the injury is unknown, but he is not expected to return to the game. More details to come when we have them.

UPDATE (8:40): Just received confirmation from Vikes' PR that it was Jackson's right knee that was injured.

UPDATE (10:18 p.m.): Brad Childress, speaking to KSTP-Ch. 5:

"He's fine. He just got bumped in the knee. We'll just keep him in there. Got some ice on it at half. Just a little contusion there."