The Portland Mavericks are a baseball team located in Keizer, Oregon, who are charter members of the Mavericks Independent Baseball League, a four-team league created in 2021. The entire league, including the Mavericks, will play their games at Volcanoes Stadium in the Salem Metropolitan Statistical Area. The owners of the Salem-Keizer Volcanoes, a former San Francisco Giants' Minor League Baseball affiliate, bought the rights to the Mavericks to help create the league after the Giants ended the affiliation in 2020.

Prior to the Mavericks League, the Mavericks were an independent team based in Portland, Oregon. After the 1972 season, the Portland Beavers of the Pacific Coast League left Portland to become the Spokane Indians. The next year, the Mavericks were created as a short-season Class A team in the Northwest League. The team operated as an independent club in Portland for five seasons, until the Pacific Coast League returned in 1978. The Mavericks played their home games in Civic Stadium.

The Portland Mavericks were an independent professional baseball team in the northwestern United States, based in Portland, Oregon. They began to play in the short-season Class A Northwest League in 1973, after the Portland Beavers of the Pacific Coast League left after the 1972 season and became the Spokane Indians. The Mavericks operated as an independent club in Portland for five seasons, until the return of the PCL in 1978, and played home games on artificial turf at Civic Stadium in Portland.

The Mavericks were owned by ex-minor league player and television actor Bing Russell, and were initially the league's only independent club. As owner, Russell kept all corporate sponsorship outside the gates, and hired professional baseball's first female general manager, as well as the first Asian American general manager.^{[citation needed]} Russell's motto in life was one three-lettered word: "fun."

Ex-major leaguers and never-weres who could not stop playing the game flocked to the team's June try-outs, which were always open to anyone who showed up. Most of the Mavericks players were older than their opponents and had been released by other organizations, not all for baseball reasons alone. For this reason, Russell kept a 30-man roster because he believed some players deserved to have one last season.

Among the various castoffs who made up the Mavericks' roster was former major league pitcher Jim Bouton, who made a comeback with the Mavericks in 1975 after having been out of baseball since retiring in 1970.

Bing Russell's son, actor Kurt Russell, played for the club for a month in its inaugural season in 1973. The first-year Mavericks' Hollywood connection was not limited to the Russells; manager Hank Robinson (1923–2012) was a character actor, and players Robbie Robinson, Jason Tatar, and Ken Medlock all had long careers as actors. Perhaps the team's most successful Hollywood story is that of Maverick batboy Todd Field, who went on to have a long career as an actor before becoming a six-time Academy Award-nominated writer and director.

Open tryouts for the team in early June 1973 drew 150 hopefuls, including one who hitchhiked across the country from Tennessee. Longtime minor-league star Hank Robinson managed the Mavericks to a record of 45–35 and a South Division title in 1973, their first season, but was suspended for a year after punching an umpire in late August. The players were paid $300 per month.