Nicky Hayden withdraws from Valencia test due to wrist injuries

The American was one of four riders eliminated when Alvaro Bautista lost control of his Suzuki at the start of the race and slid into the pack.

Although initially given a clean bill of health after X-rays on Sunday, the 2006 world champion was diagnosed with non-displaced fractures of the right scaphoid and radial styroid.

"This morning I put my leathers on to go out, but I was still pretty uncomfortable," Hayden said. "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."

Ducati replaced Hayden with test rider Franco Battaini, who worked on initial set-up work with Valentino Rossi.