Ken Holtzman, mustachioed Cubs picture from the 1970s...
He was traded by the Cubs to the A's after the 1971 season, just in time to join the team that would win 3 straight World Series. The 1972 rotation: Vida Blue, Catfish Hunter, Ken Holtzman, Blue Moon Odom
As a publicity gimmick, A's owner Charlie Finley offered each player I want to say $500 to grow a mustache. He's also the one who bestowed nicknames like ''Catfish'' and ''Blue Moon'' on some of the players.
This was the early days of free agency, an arbitrator had ruled that the reserve clause binding a player to the team was no longer in effect after a year without a contract, so if a player didn't sign his contract and ''played out his option'' he would then become a free agent. Nine of the A's refused to sign contracts for the 1976 season so Finley tried to trade them before losing them, trading Ken Holtzman along with Reggie Jackson to Baltimore.
An uncle lived in San Jose, so every year we'd visit and he'd take my brother and I to an A's game and a Giants game.