Gaines Adams, a defensive end for the Chicago Bears, died Sunday morning in South Carolina, according to the county coroner. Adams was 26.
County coroner James T. Coursey told the NFL Network that "health issues" prompted Adams' girlfriend to call an ambulance. Coursey also said Adams had no history of health problems.
A spokesman of the Greenwood County coroner's office said a preliminary autopsy indicated Adams died of cardiac arrest, caused by an enlarged heart.
The Bears released a statement Sunday afternoon: "We are stunned and saddened by the news of Gaines' passing. Our prayers are with his family during this difficult time."