After struggling with his healing shoulder during the first MotoGP test of 2012 at Sepang last week, Nicky Hayden travelled directly to California for a thorough examination at Doctor Arthur Ting's clinic.
There, tests revealed damage to cartilage in the American's shoulder, as well as to muscles in his back.
As a result, the Ducati rider will undergo an operation on Monday to have his condition evaluated more thoroughly, and to treat his injuries.
"Of course another operation before the season is never a good thing," Hayden said, "but I'm actually happy that I tried to ride at Malaysia, because it helped me to discover that the problem with the shoulder was bigger than we thought. After seeing the scans, it was clear why I couldn't ride well.
"Setbacks are a part of life and a part of MotoGP, so we'll deal with it and do everything possible to get back on the bike in good condition as soon as possible. Ducati and the team are putting maximum effort into this championship, and that helps me to keep my spirits high and to be confident heading into the season."
The 2006 world champion, who missed last November's Valencia post-race test due to an injury in the race, broke his left shoulder blade and fractured two ribs while training at an indoor flat track on December 27.
However medical checks shortly after the accident suggested that surgery was not needed.
The operation surely means Hayden will not be able to take part in a private test session at Jerez from February 20-22 - proposed to make up for his lost laps at Sepang and Valencia.
The second Sepang MotoGP test starts just one week later, on February 28.