Thoracic outlet syndrome is the compression of nerves and blood vessels in the lower neck and upper chest, and the procedure often involves removing a rib to alleviate that pressure.
The 29-year-old right-hander was placed on the disabled list after his lone 2016 start with inflammation in his right shoulder and was doubtful to return to the team this season. In late April, an MRI revealed that Ross wouldn't require surgery and he tried multiple times to rehab the injury, but he finally opted to have surgery after visiting multiple specialists.
Ross, who will be a free agent after the 2017 season, hopes to be ready for spring training. He has a 32-53 career record with a 3.64 ERA.