EDEN PRAIRIE, Minn. (AP) - The Minnesota Vikings were excited about the progress Letroy Guion was making in his transition from one defensive tackle spot to the other.

He showed up in ideal shape, had a positive attitude about the new position and hustled all over the field.

There's one problem. He's hurt now and might not play the rest of the preseason.

Guion sprained the posterior cruciate ligament in his right knee on Aug. 11 during the first series of the game at San Francisco. He sat out against Buffalo last Friday, but he was back on the field this week wearing a brace until he aggravated the injury in practice on Tuesday. Guion watched from the side on Wednesday wearing a white compression sleeve over his knee, and he won't play this week against San Diego.