St. Louis outfielder Chris Duncan will have surgery on Monday to repair a herniated disk in his neck which will likely sideline him for the rest of the season, according to ESPN.com. Duncan, who went on the disabled list in late July, had been batting .248 with 27 RBIs in part-time duty. He said the neck has been bothering him for a while. "He had a little bit of relief the past day or two, but he's in a lot of pain," Cardinals' Manager Tony La Russa said Friday. "He's dealt with a lot of pain and he's played a lot when he hasn't been right. He's caught a lot of [unnecessary heat] from people. It's not my favorite subject."