Minor League manager Geren was hired by then
Boston Red Sox director of player development
Bob Schaefer to manage in the Red Sox minor league system. He managed for the Red Sox from 1995 to 1998 at the Rookie and Class A levels before leaving to join the Oakland Athletics' organization. Geren managed the Athletics'
Single-A affiliate
Modesto A's during the 1999 season and won the
California League Manager of the Year award. He next was named the first-ever manager of the Oakland Athletics'
Triple-A affiliate
Sacramento River Cats. Geren managed the River Cats for three seasons (2000–2002). During his managing in the Athletics' minor league system, Geren worked under A's General Manager
Billy Beane, a longtime friend and former high school baseball opponent. Under Geren's management, the Rivercats won
Pacific Coast League division titles in 2000 and 2001. During the winter, Geren managed the
Tigres del Licey in the
Dominican Baseball League, winning the league championship in the 2001–2002 season. In February 2002, Geren led Licey to a second-place finish in the
2002 Caribbean Series held in
Caracas, Venezuela. The 2002
Dominican Republic team included notable MLB players
Vladimir Guerrero,
Miguel Tejada, and
Odalis Perez. Geren later returned to the Dominican Republic in the winter of 2005 to manage the
Leones del Escogido. Geren's lifetime minor league managerial record was 452–390. Geren was called to the major leagues in 2003 where he first served as the
bullpen coach for the
Oakland Athletics. Geren was eventually promoted to
bench coach, a position he held through 2006.
Oakland Athletics manager On November 17, 2006, Geren was promoted from his previous position as Athletics bench coach to become the 28th manager in Oakland Athletics franchise history. He replaced
Ken Macha, who was fired after disagreements with players and
general manager Billy Beane. In 2007, Geren led the A's to a 76–86 record. In 2008, the Athletics finished the season with a 75–86 record. In March 2009, the A's and Geren agreed to a contract extension for one year, with an additional options year. During the 2010 season, the A's finished with an even .500 winning percentage (81–81 record). On September 11, 2010, MLB.com announced that Oakland had exercised Geren's option for 2011, assuring him another season in the green and gold. In May 2011, Geren's managerial style came under scrutiny by Bay Area press when reliever
Brian Fuentes criticized Geren's communication style after he was replaced as the A's closer amid poor performance in the role. Fuentes later apologized to Geren for going public with his comments, and A's owner
Lew Wolff endorsed Geren as the A's manager. Geren's last game as manager was June 9, 2011; he was subsequently fired and replaced with
Bob Melvin.
New York Mets during the
2015 World Series. On October 14, 2011, the
New York Mets hired Geren to be the team's new bench coach replacing former bench coach
Ken Oberkfell. During the 2015 season, the Mets won the
National League Championship Series and played in the World Series against the
Kansas City Royals. The Royals eventually won the
2015 World Series in five games. During his time with the Mets, Geren was praised for his "statistical aptitude" and "strong working knowledge of advanced analytics." Mets General Manager Sandy Alderson also complimented Geren for being "tuned into analytics."
Los Angeles Dodgers On December 2, 2015, it was reported that the
Los Angeles Dodgers hired Geren to be the team's new bench coach serving under new manager
Dave Roberts and replacing former bench coach
Tim Wallach. Geren said his decision to leave the Mets for Los Angeles was fueled by a desire to be closer to his family in Southern California. During the 2016 season, his first with the Dodgers, Geren coached under manager Dave Roberts, who would go on to win the 2016 National League
Manager of the Year Award. In 2017, the Dodgers won the National League Championship Series and played against the
Houston Astros in the World Series. In 2018, the Dodgers appeared in their second straight World Series and played against the
Boston Red Sox. Geren won his first
World Series in the 2020 season, as the Dodgers defeated the
Tampa Bay Rays in six games. For the 2023 season, Geren transitioned from his role as bench coach to take on the newly created coaching position of major league field coordinator. In the 2024 and 2025 seasons, Geren won back-to-back World Series championships with the Dodgers. ==Personal life==