As one of the game's first every-day catchers, The Sporting News in 1949 called Zimmer "baseball's original 'iron man'." Offensively, Zimmer had a career batting average of .269, but hit above .300 four times, including a career-high .340 batting average in 1895.
Zimmer is regarded by some as "the finest defensive catcher of his day." He set major-league catching records for assists (188 in 1890), double plays (16 in 1895), runners caught stealing (183 in 1893), games at catcher (125 in 1890), and career fielding percentage (.943 as of 1896).