On August 22, 2000, the Colorado Rockies sent Mayne in as a relief pitcher in the 12th inning against the Atlanta Braves. Mayne, the Rockies' regular catcher, was unable to swing a bat due to a sprained left wrist and had missed the previous four games. Out of pitchers, manager Buddy Bell asked Mayne if he could pitch. Mayne, who later said he had never pitched at any level, responded, "Yeah, I can pitch."[4] He pitched one inning, surrendering no runs with a fastball that topped out at 83 miles per hour. Colorado won the game in the bottom of the 12th inning when rookie Adam Melhuse, pinch-hitting for Mayne, singled with the bases loaded and two outs. Mayne thus became the first position player pitcher to be credited with a win since Rocky Colavito in 1968, and the last to do so until Wilson Valdez in 2011.
In a 15-year career, Mayne was a .263 hitter with 38 home runs and 403 RBI in 1279 games.
Mayne was inducted into the Orange Coast College Hall of Fame in 2006 and into the Cal State Fullerton Hall of Fame in 2011.[5]