The surgery was performed by noted orthopedic surgeon Dr. James Andrews and assisted by Astros orthopedist Dr. David Lintner. Lyon will start motion exercises in approximately two weeks and is expected to miss the rest of the regular season.
Lyon, in the second year of a three-year, $15 million contract, went 3-3 with an 11.48 ERA in 15 games, battling arm injuries for much of the season. He blew four saves in five chances, including Opening Day in Philadelphia, before going on the DL.
Lyon, 31, went 6-6 with a 3.12 ERA in a career-high 79 games for the Astros last year, saving 20 games in 22 chances. He allowed only two homers in 78 innings, but this season he had allowed four homers in 13 1/3 innings.