Harrison, 32, underwent surgery Monday morning, a week after the procedure was delayed when Harrison came down with a fever.
The procedure, known as a discectomy, involved removing a piece of herniated disc off a bothersome nerve.
"Everything went great," said Bill Parise, Harrison's agent. "The consensus was no one could figure out how he could play through the season. It was significant but textbook. The surgery went exactly as they wanted it to. James' recovery should be complete."