The 29-year-old Texan had signed a two-year agreement with Ducati at the end of last season to race in MotoGP in 2013 and 2014 as part of the factory-supported Ignite Pramac Racing Team.
Ducati and Spies have reached an agreement to resolve their current contract.
Spies has been sidelined for most of this season due to an injury to his right shoulder sustained in October 2012 while riding for another manufacturer team. While he began 2013 racing with Pramac, it quickly became clear that he was not fully healed from his injury and needed to undergo further rehabilitation on his shoulder. Unfortunately, on his return to racing at Indianapolis in August, Spies had another setback when he suffered a season-ending crash during practice.
As a result of the injuries, the 2009 World Superbike champion, three-time AMA Superbike Champion and MotoGP race winner announced his retirement.
“I had such high hopes for racing for Ducati, and Ducati has been incredibly supportive of me during this challenging year, so I am tremendously disappointed that I have not been able to fulfill my personal goals and team goals with Ducati," Spies said. “I want to thank everyone from racing organizations, factories, teams and all my fans for helping me and supporting me throughout my career. I never dreamed that I would reach the level of success that I have over the past 20 years of racing, but the time has come to stop and I do so with great sadness."
“We had high expectations when Ben joined Ducati in MotoGP this year, and we really hoped that he would fully recover from his Indianapolis crash injuries and continue to race for us in the future," said Ducati MotoGP Project Director Paolo Ciabatti. “However, we understand the reasons for his decision and respect them. It is really a shame for our sport that Ben will not be racing anymore, because in our opinion he is one of the most talented riders in the world. We will miss him and wish him all the best for his future life."