In his eight-year career, Mayer played for the Philadelphia Phillies, the Pittsburgh Pirates, and the Chicago White Sox.

A right-handed pitcher, Mayer's repertoire of pitches included a curveball which he threw from a sidearm angle.

[1] As a result of his curveball, then Brooklyn Dodgers manager Wilbert Robinson called Mayer "Eelskine" because the pitch was "so slippery.

He was one of the all-time best Jewish pitchers in major league history through 2010, 3rd career-wise in ERA (behind only Barney Pelty and Sandy Koufax), 7th in wins, and 10th in strikeouts (482).

[4] His paternal grandparents were Jews who immigrated to the US from Germany, and his father Isaac was a concert pianist and music teacher, and composed an opera in Hebrew.

[4] In 1910, after three years of school, Mayer left Georgia Tech to pursue a career in professional baseball.

When Mayer left Georgia Tech in 1910, he signed first with the Atlanta Crackers and then with the Class-D Fayetteville Highlanders of the Eastern Carolina League.

[4] In 1911, Mayer played for the Albany Babies of the South Atlantic League where he won 14 games and lost 13.

[4] On September 4, 1912, Mayer made his major league debut as a member of the Philadelphia Phillies in their game against the New York Giants.

In the ninth inning of the Phillies August 18 game against the Chicago Cubs, Mayer set the Major League Baseball record for consecutive hits allowed (9).

It was a record that remained unmatched for less than 24 hours as teammate Grover Cleveland Alexander repeated the feat the very next day.

[7] Mayer started the 1919 season with the Pirates; however, in August of that year, the Chicago White Sox selected him off waivers.