The procedure, which included decompression and transposition of the ulnar nerve, was performed by Dr. George Paletta, the Cardinals' team physician.
The surgery is not expected to interfere with the physical rehabilitation of Carpenter's shoulder, which forced an end to his 2008 season. Carpenter was stopped pitching in September after just four appearances because of persistent shoulder weakness.
Carpenter strained his right triceps in early August and went on the disabled list. After being activated, he tossed an inning of relief Sept. 2, but felt further weakness. He had his shoulder evaluated and tests confirmed a strain of the teres major and indicated new nerve irritation in the shoulder.
The 2005 NL Cy Young Award winner has a career mark of 100-70 and a 4.08 earned-run average in 250 games, including 232 starts, over parts of 11 seasons for Toronto and St. Louis.