Dr. James Andrews recommended the surgery, confirming the original diagnosis of a small tear in his labrum. He is said to have what was described as a "30-40" percent tear, requiring surgery. The Cardinals' team doctor George Paletta will perform the operation.
Garcia, 26, is expected to return to the mound for the Cardinals next year.
Andrews is said to have expressed the opinion to Garcia that it's amazing he was able to pitch as well as he did considering the condition of his shoulder. Garcia was 5-2 with a 3.58 ERA before having to visit the doctors with shoulder pain.
Garcia received criticism during last year's postseason when he was removed after just two innings in Game 2 of the NL Division Series against the Nationals, but now it is clear he has a serious shoulder issue. He felt discomfort in warmups before that Game 2 start but tried to give it a go before being removed.
Garcia actually had started to feel soreness a couple days before that start but said at the time he felt well enough to try to pitch. The Cardinals wound up winning the game, and the series, but Garcia was lost for the postseason.
After rehabbing the shoulder all winter, Garcia tried to pitch through his shoulder issue this year, and for a while, it seemed to be working. His performance was right in line with his career record (he's now 39-25 with a 3.45 ERA) despite having the tear.
He started to feel the shoulder discomfort again about two weeks before going on the disabled list Saturday, and was diagnosed with what was described as the same issue as last October.
Garcia was quoted by MLB.com on Saturday saying, "I'm very concerned, especially, the way I felt last night and the way I feel today."