Nicky Hayden's participation in the first MotoGP test of 2012 is in doubt after the American was injured while training in Kentucky.
Hayden was riding a bike for the first time since he broke his scaphoid at the Valencia Grand Prix in November when he crashed with another rider and landed on his shoulder.
The American broke his left scapula and fractured two ribs.
Ducati said there are no plans for surgery at the moment, but Hayden will have the scapula reassessed next week to check its progress.
The next few weeks will determine whether he will take part in the first winter test of 2012, which will begin on Jan. 31 at Sepang.
"Obviously, injuries are never good," Hayden said, "but it's part of motorcycle racing. Just like at Valencia, it was kind of a freak accident. I was starting to train again, like I normally do during the winter, at a private track near my house.
"I came up behind another rider, and he went to move out of the way. I wasn't going that fast, but he clipped my front wheel and I went down and landed pretty hard on my left shoulder, and that was it.
"It's disappointing, but there's nothing to do about it but heal quickly. Anyway, this doesn't change my expectations for 2012 which, fortunately, is just around the corner."