"Percy Harvin missed Thursday's Vikings practice because of an illness, but coach Leslie Frazier said it's likely a stomach virus, not a migraine, and that the receiver was expected to return Friday.

"We've gone through the migraine part [before]," Frazier said. "There's a distinct difference with what's happening with your stomach and what's happening with migraines."

Harvin has battled migraines on and off since he was 10. He has missed three games since joining the Vikings in 2009, including two last season.

Harvin was sidelined briefly in training camp because of a rib injury but has not had a migraine yet this season. He hasn't missed a practice during the regular season and was at Winter Park for meetings early Thursday."