The Fresno Grizzlies have been the Triple-A affiliate of the San Francisco Giants in the Pacific Coast League since 1998, when professional baseball returned to the city after a ten-year absence.
Professional baseball first came to Fresno in 1898 when it had a team in the original California League. The team dropped out of the league after that year, but returned in 1905. In 1906, the Tacoma Tigers of the Pacific Coast League moved to Fresno, playing as the Fresno Raisin Eaters for one season before moving to Sacramento for the 1907 season. In the intervening years before the arrival of the Grizzlies, Fresno fielded teams in the California State League in 1910 and 1913, and in the current California League from 1941 through 1988, including the Fresno Cardinals (1941-1956), Fresno Sun Sox (1957), Fresno Giants (1958-1987), and Fresno Suns (1988).
When the Arizona Diamondbacks expansion franchise was awarded to Phoenix by Major League Baseball with a start date of 1998, the existing Phoenix Firebirds PCL team, at the time the Giants' Triple-A affiliate, was forced to relocate. The owners of the Firebirds moved their team to Tucson and became the Tucson Sidewinders, dropping their affiliation with the Giants in favor of the expansion Diamondbacks.
The owners of the existing Tucson Toros then moved their franchise to Fresno, ending a 92-year hiatus of PCL baseball in Fresno. The transplanted Toros, renamed the Grizzlies, became the Giants' new PCL affiliate.
For the organization's first four seasons, the team played at Pete Beiden Field on the campus of California State University - Fresno. In 2002, the club moved into what was then known as Grizzlies Stadium, and is today known as Chukchansi Park.