Keightley was on a trip Monday to Cincinnati to see the Reds season-opener and suffered a fall. He was taken to University Hospital in Cincinnati, where he died of internal bleeding at 7:45 p.m. EDT.
Doctors apparently found an undiagnosed tumor on Keightley's spine and that the fall was probably due to the bleeding.
Keightley served as the manager for Kentucky basketball for 48 seasons, watching Kentucky win 1,113 games. He served under six UK head coaches from Adolph Rupp to Billy Gillispie.
He and Cawood Ledford are the only two non-players or coaches to have a jersey retired in the Rupp rafters.