Long before the city of Santa Clara, California was home to Levi's Stadium and the San Francisco 49ers of the NFL, the city's only other professional sports team in modern history was the Santa Clara Padres, a co-op team in the single-A California League. Their lone season was in 1979, where they were supposed to play their home games at Washington Park, a WPA project which was built in 1935 and featured a wooden 1,000-seat grandstand. However, minor league baseball was unsatisfied with the small park and so the Padres played many home games at nearby San Jose Municipal Stadium instead, which they had to share with then-Mariners affiliate the San Jose Missions. The Santa Clara Padres featured players from the Mariners, A's, Angels, Padres, and Cardinals organizations.Three future major leaguers played for the team; John Hobbs, Ron Tingley, and the one-and-only Joe Maddon, who caught 60 games behind the plate.
Santa Clara Padres Cap: Gold logo identical to the USC Trojans, maroon crown, kelley green button and visor. It was also a mesh snap-back. The colors were meant to be a tribute to the many Portuguese, Italian, and Mexican families that call Santa Clara home.
After a disastrous 47-93 season under manager Joe Volpi and the lowest attendance in the league, the team moved north of San Francisco to the Sonoma County town of Rohnert Park where they became the Redwood Pioneers for the next five seasons. They then became the Palm Springs Angels, and since 1994 are now the Lake Elsinore Storm.
Washington Park still stands today and is used today by local youth leagues as well as hosting games for the local "vintage" league that plays by 1860s rules. I watched a vintage game there myself in 2013.
Note: I do not personally own a Santa Clara Padres cap, although I wish I did. The photo was sent to me by someone that owns one.