History of the San Francisco Seals baseball team – charter members of the Pacific Coast League (LCL). From the SFO Museum.

San Francisco Seals playing at Recreation Park 1927

Dario Lodigiani of the Oakland Oaks sliding into third base 1937

Seals and New York Giants in exhibition game at Seals Stadium 1947
Excerpt:
Before the arrival of the Giants from New York in 1958, the Seals were San Francisco’s favorite professional baseball team and an integral part of the city’s fabric.
There were no Major League Baseball teams west of St. Louis during the first half of the twentieth century and no televised baseball games either. The PCL was very successful, and stadium attendance was often greater than that of their Major League counterparts in the Eastern and Midwestern regions.
Photos: Courtesy of the San Francisco History Center Photography Collection, San Francisco Public Library, California
+ Source: The Local Nine: San Francisco Seals Baseball ::1903-1957 :: SFO Museum