Dr. James Andrews repaired the ulnar collateral ligament in Morton's right arm Thursday in Pensacola, Fla.
The 28-year-old pitcher went on the 15-day disabled list on June 1 with inflammation in his right elbow. He was 2-6 with a 4.65 ERA in nine starts this season.
Recovery time from the operation, often referred to as Tommy John surgery, is 12-18 months.
Obtained from the Atlanta Braves in June 2009, Morton finished that season 5-9 with Pittsburgh. He was 2-12 in 2010 before rebounding to go 10-10 last year. He led the team with 171 2-3 innings and ranked second in wins behind Kevin Correia.