Manager Fredi Gonzalez made the announcement after the Braves beat the New York Yankees on Wednesday, hours after Beachy received a second opinion from Dr. James Andrews.
The 25-year-old Beachy was put on the 15-day disabled list Sunday, a day after leaving a start early. He is tied for the major league lead with a 2.00 ERA and is 5-5 in 13 starts.
Andrews has performed many of the ligament replacement operations known as Tommy John surgery. Recovery time for the injury normally takes 12-18 months.
Jair Jurrjens will be recalled from Triple-A Gwinnett to start Friday in Boston.