Factory Ducati MotoGP star Nicky Hayden will miss this week's Valencia test after being diagnosed with a broken right wrist.

The American was one of four riders to fall in turn one of Sunday's season-ending Valencia Grand Prix (pictured).

However the full extent of the wrist injuries - non-displaced fractures to his scaphoid and radial styloid - were only discovered on Tuesday.

"This morning I put my leathers on to go out, but I was still pretty uncomfortable," said Hayden. "I went to the mobile clinic for a painkiller, and when I got there, the doctor said it would be better to get a proper scan.

"They set me up for an MRI at a local clinic, and the fractures were pretty clear. After talking to the doctor and my physiotherapist, we decided not to ride, even though we do have some stuff we'd like to test for Ducati.

"The scaphoid is a unique bone, and if you mess with it, it can take a long time to heal because it gets limited blood supply. I just have to be smart and watch the test. We'll get some more opinions and decide whether to get surgery."

The two-day Valencia test ends on Wednesday evening.