Jeff Sperbeck, John Elway's longtime business partner, is in the hospital on life support ... following a horrific golf course accident over the weekend, TMZ Sports has learned.
We're told Sperbeck was at The Madison Club in La Quinta, CA on Saturday afternoon, riding on the back of a golf cart, when something went terribly wrong ... and Jeff somehow fell off the moving vehicle, landing on the ground, and hitting his head.
Jeff's wife and at least one other person noticed Sperbeck was down and quickly turned around to check on him.