Viking wide receiver and reigning Offensive Rookie of the Year Percy Harvin suffered a scary incident on Thursday, collapsing at practice and ultimately leaving the field by ambulance after suffering a migraine headache. Harvin, a chronic migraine sufferer, was resting comfortably in a Minnesota hospital where he remained overnight.

Migraines headaches are unpredictable and serious issue for athletes, particularly NFL players. Like in the case of Harvin, migraines can begin at an early age. However because a migraine is largely defined by information provided directly by the patient, they often go undiagnosed. They are classified by significant head pain that is often accompanied by nausea, sensitivity to light, and potentially vomiting and loss of consciousness. Often a migraine will be preceded by an aura, a warning sign of an impending episode. An aura can be flashes of light or a tingling sensation in the extremities. While the exact root of the problem is unknown, several factors including stress, physical exertion, and weather changes are believed to contribute to triggering a migraine. Medication exists to treat the associated symptoms and help reduce the regularity and severity of migraines, but at this time an end-all cure does not exist.

Harvin has been plagued by migraines since he was a young boy. The problem continued throughout his college career at Florida, sending him to the hospital his sophomore season. He sat out a game against the Bengals last season and has already missed time during this year's training camp with the ailment. He visited the world renowned Mayo Clinic last year in an attempt to develop a plan of action to help prevent and control his headaches. It seems likely that the rigors of training camp and the emotional stress from the recent passing of his grandmother may have contributed to his latest bout of migraines. The particular episode that sent Harvin to the hospital was triggered when he gazed into the sun while fielding a punt during special teams.

The migraines are likely to affect Harvin's availability throughout the year and are a major cause for concern for the Vikings, their fans, and fantasy owners. However Thursday's incident served as an eye-opener for many and was a reminder that the health and well-being of a player takes priority over all else.