It was sunny and slight cool but warmed up after lunch. Bob, Sonny, Doug and John were on the ride. The pace was relaxed for the majority of the ride except the descent down Soquel and the Climb up Mt. Madonna. We rode past a lot of farm fields and some pretty forested areas. Bike and legs felt great all the way up until Eureka Canyon. It is my least favorite road EVAR!!! Really bad potholes on the climb and the descent make it anywhere from annoying to dangerous. During the faster lower section John was in the lead. Sonny past him and then I past him as well. Right when I was beside John, in my peripheral vision I saw John catapult into the air. There was a huge pothole in the road and rather than jump it or roll over it, I think John grabbed his brakes sending him forward and then the front tire bit on the lip of the pothole and over he went. I think he ended up 20-25' from the pothole. He lay by the side of the road until medical help arrived. His bike ended up in a ditch another 20' down the road. I was going 30mph at the time and John was probably going 25-27mph. Once again Doug got a great view of the action at the back but nearly got taken out by John's runaway bike. His helmet was pretty banged up. He said his right shoulder hurt but he didn't think he broke anything. Fortunately the fire department was just up the road. They came pretty quickly. Eventually he was taken to the hospital by ambulance. He broke his clavicle. We finished up the ride with a very strong headwind on the descent of Old Santa Cruz all the way back to the car.