He played in Major League Baseball (MLB) as a catcher between 1933 and 1947, most prominently as a member of the Philadelphia Athletics where he became a six-time All-Star player.

[1] Although Hayes was considered one of the best catchers in the American League in the late 1930s and early 1940s, he played for an Athletics team that routinely finished in last place.

[5][7] In September 1934, Hayes joined a group of American baseball players led by Connie Mack in a barnstorming tour of Japan when Charlie Berry, who had originally been selected to go, was struck with appendicitis.

[5] Among the baseball players who joined Hayes in Japan were Babe Ruth, Lou Gehrig, Jimmie Foxx and Charlie Gehringer.

[9] Hayes returned to the major leagues in 1936, replacing Paul Richards as the Athletics starting catcher, a position he held for six seasons.

[1] Hayes' on-base percentage also improved from .348 in 1939 to .389, and was once again named as a reserve player for the American League team in the 1940 All-Star Game.

[16][17] After hitting for only a .188 batting average in 1943, it appeared as if his baseball career might be at an end when Connie Mack brought him back to the Athletics in a trade for Sam Zoldak in February 1944.

[22][23] Contemporary news reports expressed astonishment over the trade, as Hayes was considered one of the best catchers in the league while Rosar was refusing to play for the Indians due to a salary dispute.

[27] In the middle of the 1946 season while mired in a hitting slump, Hayes had a falling out with Indians' manager Lou Boudreau over being benched in favor of Sherm Lollar.

[1] He led the American League three times in total chances per game, twice each in putouts, double plays, and once each in assists and fielding percentage as a catcher.