The Twins traded Beane to the Detroit Tigers for Balvino Gálvez during spring training in 1988. He made the Tigers' opening-day roster that season as an injury fill-in, and was optioned in late April to Toledo, now serving as Detroit's Class-AAA affiliate, where he spent most of the season. During this time, he played in the same outfield as another player with nearly the same name – Billy Bean – and also had a teammate with the name Rice. Beane appeared in six games for the 1988 Tigers. Granted free agency after the 1988 season, Beane signed with the Oakland Athletics, appearing in 37 games with the 1989 Athletics, batting .241 in 79 at bats. Beane spent most of the season with the Class-AAA Tacoma Tigers of the PCL. He re-signed with the Athletics for the 1990 season, and was sent down to the minor leagues at the end of spring training.