In the surgery, a cartilage flap will be removed from Wainwright's elbow. The cartilage flap helped to cause a bone bruise to his right arm and is being blamed for the right-hander's decrease in velocity in the second half.
"Unfortunately, I couldn't get over that bone bruise in there," he told reporters.
"I just needed time, and I didn't have time. I took enough time off where we thought we could go back out and pitch for an extended amount of time, and you saw what happened. I was throwing better, but it was the same kind of stuff -- lower velocity, couldn't get finish on my breaking balls. It was frustrating because I really wanted to help the team, and I really wanted to be here down the stretch when we were so close," he said.
The estimated recovery time is six weeks. The 36-year-old pitcher said Sunday that he expects to be healthy in time for next season.
This will be the second surgery Wainwright has had on his right elbow. He underwent Tommy John surgery in 2011.
The three-time All-Star finished 12-5 this season with a 5.11 ERA.