Apparently he was training with Lance in Austin TX. He stopped for some reason. Then when he resumed, he tried catching up to Lance.
He hit a pothole which ejected him from his bike. During the impact, he hit his chest against his stem and damaged fracturing his sternum, and fractured a vertebra in his back when he impacted the ground. He's likely to head back to Europe for his recovery. But his spokesman are saying he won't be back for several weeks and possibly months.