The 2013 Oakland Athletics season was the 45th for the franchise in Oakland, as well as the 113th in club history. Oakland was defending their division title in the new five-team American League West during the 2013 season. On September 22, 2013, they clinched their second straight American League West championship. They lost to the Detroit Tigers in five games in the 2013 American League Division Series.

Following a successful 2012 season in which the team won the AL West, GM Billy Beane stated he would keep the team mostly intact, and "if moves are made, they will be additions".^[1] The first acquisition occurred October 19 in a three-team trade involving Arizona and Miami; Oakland sent Cliff Pennington to Arizona and minor leaguer Yordy Cabrera to Miami, and the team received Chris Young from Arizona. In November, the team traded pitcher Tyson Ross and minor leaguer A. J. Kirby-Jones to San Diego for infielder Andy Parrino and pitcher Andrew Werner. Grant Green, Arnold Leon, Shane Peterson, and Michael Ynoa were added to the 40-man roster and Andrew Carignan, Brandon Hicks (who was traded to the Mets) and Jim Miller (who was claimed off waivers by the Yankees and later designated for assignment) were removed. The next move was to trade Collin Cowgill to the Mets for Jefry Marté. When free agent Stephen Drew signed with the Boston Red Sox, Oakland signed Japanese shortstop Hiroyuki Nakajima to a 2-year, $6.5 million deal, with an option for a third year, in order to fill the vacancy. Pitcher Graham Godfrey was sent to Boston as a player to be named later to complete a previous trade, while Brandon McCarthy and Jonny Gomes, who both elected free agency, signed with Arizona and Boston, respectively. In January, Oakland was involved in their second three-team trade of the offseason, trading pitching prospect A. J. Cole back to Washington (he was part of a trade for Gio González the year before) and receiving catcher John Jaso from Seattle. Upon the acquisition of Jaso, George Kottaras was designated for assignment. In February, the A's were involved in a five-player deal with new division rival Houston, trading Chris Carter, Brad Peacock and Max Stassi in exchange for shortstop Jed Lowrie and reliever Fernando Rodriguez.^[2]

In addition to player movement, there was also a coaching change made by the Athletics. Bullpen coach Rick Rodriguez was offered a position within the organization, and Darren Bush, the manager of the Triple-A affiliate Sacramento River Cats, will assume bullpen coaching responsibilities.

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