(AP) - Cardinals manager Mike Matheny planned to leave the team after Sunday's spring training game and return to St. Louis for surgery to repair a ruptured disk in his lower back. Matheny expects to be back at spring training for Thursday's game against Atlanta in Jupiter. "There is still a fragment that is stuck in a spot where it's getting to the nerve and affecting what is going on back there," Matheny said prior to Sunday's game against the New York Mets. The 42-year-old Matheny, who replaced Tony La Russa as manager after the 2011 season, said early in spring training that the injury probably traces back to his days as a big league catcher from 1994-06. "They seem pretty confident this will take care of it," he said of the surgeons. The ruptured disk sends pain into his right leg, which became severe on Feb. 28 and caused him to skip the next day's game against Houston at Kissimmee. An epidural injection on March 4 failed to relieve the pain. "We were hoping it would kind of settle down and go away, but it really hasn't," Matheny said. The pain is at its worst when Matheny stands after sitting for any length. He decided to have the surgery now, before plane trips during the regular season. "I hate that it's been as big a deal as it's been," he said. I'm anxious to get it over. Bench coach Mike Aldrete will manage the team in Matheny's absence.