Vikings rookie wide receiver Percy Harvin was not on the field as the Vikings began practice Thursday. Harvin was not on the injury report Wednesday and it's unclear what is wrong. The first thought is that Harvin is dealing with more migraine issues but hopefully we'll find out more after the Vikings complete practice.

Sitting out for a second consecutive day are left defensive end Ray Edwards (knee) and Pro Bowl defensive tackle Kevin Williams (knee). Williams was seen leaving the field after Thursday's walk-through with a sleeve protecting his left knee.

Williams' absence from the two most important days of practice has to be considered a major concern and would indicate that even if he plays he will be somewhat limited.