Ben Spies' Ignite Ducati team don't yet know when he will return to MotoGP after undergoing surgery on both of his damaged shoulders yesterday.

The American crashed heavily on his return to racing in free practice three at Indianapolis and suffered a dislocated acromioclavicular joint. While under the knife, he also had detritus and scar tissue removed from the shoulder he damaged in Malaysia last year.

"Following his fall during free practice at the Indianapolis GP, and a subsequent consultation with Ducati’s doctor, Ben Spies then underwent surgery yesterday at the North Central Surgical Hospital of Dallas," said a team spokesman.

"The intervention, performed by Dr. Daniel Cooper, was intended to repair a fifth-degree dislocation of the left shoulder’s acromioclavicular joint and to remove scar tissue from the right shoulder that had already been operated on.

"The procedure was successful, but for the moment, it’s not known how long the recovery process will take or when the Texan will return to the track. In addition to the shoulder injury suffered in the fall, Spies also strained ligaments at the base of his left hand."