Jeff Sperbeck, a close friend and business associate of John Elway, has died after an incident involving a golf cart in California.

Sperbeck fell off the back of a golf cart that Elway was driving following the Stagecoach music festival on Saturday in California, according to TMZ.

A source close to Elway told 9NEWS he is devastated by the tragedy involving his close friend.

The incident occurred at the Madison Club in La Quinta, a private golf resort community in which Elway owns a home. According to TMZ, Sperbeck was seated on the back of the golf cart when he fell off and struck his head on the pavement.

It was Elway who called 911, according to the TMZ report. The local fire department and ambulance paramedics serviced the call. The local sheriff’s department did not respond to the call, although it is now.

“The Riverside Sheriff’s Office was informed of the incident on Monday, April 28th, and opened an investigation,” public information officer Lt. Deirdre Vickers stated in an e-mail to 9NEWS. “At this time, the investigation is ongoing, and no details are available.”

Initially, TMZ reported the wives of Sperbeck and Elway were also on the golf cart, and uninjured, but have since reported it was Elway, Sperbeck and Elway’s son Jack who was riding on the cart at the time of the incident.

Sperbeck was found breathing but unconscious and transported to a local hospital.

Sperbeck had been an NFL agent to more than 100 players, coaches and executives. He was the type of agent and marketing rep who stayed in touched with his clients long after the NFL careers ended.

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