Zimmer was with Cleveland (American Association) in 1887 when he became the first catcher to play directly behind the batter on every play; previously, catchers would move farther back of the plate with runners on base. The new style soon caught on. For a decade beginning in 1889, Zimmer caught for the National League Cleveland Spiders, becoming the finest defensive catcher of his day; he repeatedly led the NL in putouts, assists, and double plays. In 1895 he batted a career-high .340. He was dealt to Louisville in mid-1899, and in January of 1900 was part of the package of players that Barney Dreyfuss lifted from Louisville to bolster the Pittsburgh Pirates when the NL went from 12 teams to 8. Waived in 1903, he was picked up by the Phillies as player-manager. He hit .220 and brought the Phillies in seventh.