Brandon Webb, the 2006 National League Cy Young Award winner and one of the most dominant starters in the game during a five-year stretch with the Arizona Diamondbacks, is officially retiring from baseball, according to his agents at Millennium Sports.

Webb, 33, hasn't pitched in the majors since 2009 because of shoulder problems. He had been pursuing another comeback attempt but announced his retirement Monday in a statement released by agents Jonathan Maurer and Mike Montana.

"With retirement, Brandon looks forward to focusing on more time with his family,'' the statement said. "He would like to thank all the countless coaches, players and friends for their support during his career.''

Webb, a University of Kentucky product, made three All-Star teams and averaged 227 innings a season with the Diamondbacks from 2004 through 2008. He won the NL Cy Young Award with a 16-8 record and a 3.10 ERA in 2006.

Webb posted a combined 40-17 record over the next two seasons but finished second in the Cy Young balloting to San Diego's Jake Peavy in 2007 and San Francisco's Tim Lincecum in 2008.