Oklahoma linebacker Austin Box has died, a spokesperson for the Oklahoma City Medical Examiner's Office confirmed to ESPN.com on Thursday afternoon.
According to multiple reports, Box was found unresponsive at a house in El Reno and airlifted to a hospital in Oklahoma City, where he died.
He was being transported to the facility for an autopsy this afternoon.
Box, a senior, was expected to be the Sooners' starting middle linebacker next season and had played three seasons at Oklahoma.
Oklahoma officials declined comment when reached on Thursday afternoon.