Matt Harrison, who missed the second half of the 2009 season after undergoing surgery to deal with thoracic outlet syndrome on his left side, and who has missed basically all of this season after undergoing two surgeries to deal with a herniated disc in his back, is going to have another surgery to deal with TOS -- this time, as to his right shoulder.
Per the linked article, Harrison expects to be ready for spring training in 2014, and the fact that this is dealing with an issue on his non-throwing shoulder makes it a better situation than if it was his left side. Harrison is quoted in the article as saying, given that he's already shut down, he might as well deal with it now.
Its the ongoing curse of the Rangers' Opening Day starter, which has struck Harrison, Colby Lewis, and Scott Feldman in recent years. Hopefully Harrison will bounce back and be as good as ever in 2014.