Percy Harvin collapsed at practice and was taken to the hospital by ambulance. Harvin has had a history of migraines and other illnesses since being drafted by the Vikings.
Via Wikipedia: Despite a stellar first year in the NFL, Harvin suffered a string of illnesses. On April 30, 2009, while en route to a Minnesota Vikings rookie mini-camp, Harvin fell ill and was hospitalized prior to changing planes in Atlanta. He was released the following day. Vikings coach Brad Childress said Harvin was dehydrated and had a virus. Additionally, Harvin did not participate in the 2009 NFL Rookie Symposium due to illness and also missed the team's first three practices and first two days of training camp at Minnesota State University Mankato.Further, Harvin did not play in the Vikings 30-10 victory over the Cincinnati Bengals in week 14 due to inexplicable migraine headaches, which also prevented him from practicing the following week. However, he did play in the Vikings week 15 overtime loss to the Chicago Bears, but missed two postseason practices before the New Orleans Saints playoff game, due to migraine headaches.This is something you have to take into consideration if your thinking of drafting Harvin or you already have. It doesn't seem that he's getting any better, and actually getting worse. He only missed 1 game last year but with his migranes getting worse, he might be forced to miss more games this year.