He played in Major League Baseball as a shortstop from 1971 to 1979 for the Washington Senators / Texas Rangers, New York Yankees, Toronto Blue Jays, and Montreal Expos.

In his only plate appearance of the series, Mason hit a home run off Pat Zachry.

This turned out to be Mason's only postseason appearance, and the Yankees' only home run of their four-game series loss.

[2] Because of Mason's low batting average, which hovered just over .200, his name, along with that of catcher Leo Dixon, was proposed for inclusion in a new term for poor hitting called the Mason Dixon Line (.204), which is closer to .200 than the Mendoza Line of Mario Mendoza (.215).

[3] Mason is one of a handful of players to hit four doubles in one game, doing so while with the Yankees against his former team, the Rangers, at Arlington Stadium on July 8, 1974.