Although it was against the rules for college players to earn any money from their sport, this was a widely violated rule. Scores of college-age men played in the minor leagues over the summer under assumed names, and in 1921, months after graduating from high school, Gehrig was one of them. He signed a contract with the Hartford Senators, a Class A team affiliated with the New York Giants. For two weeks he played under the name "Lou Lewis," but then Columbia found out and forced him to quit. Gehrig lost his eligibility to play for Columbia for one year as a result, but for the next two summers he played semi-professional baseball on Sunday afternoons with a Morristown, New Jersey team as Lou Long. This was widely known, but no one is sure whether Columbia never found out this time, or whether they knew and decided to ignore it.
Gehrig played his one and only season of baseball for Columbia, as a pitcher, in 1923. He was almost instantly heralded as a star. In one game, he set a record for number of strikeouts—seventeen—which would stand at Columbia for almost fifty years. In another, he hit the longest home run ever at Columbia's South Field: it bounced off the steps of the library across 116th street, nearly beaning the dean of the college. Through such feats, Gehrig caught the eye of New York Yankees scout Paul Krichell, who offered him $3,500 to sign with the Yankees. Gehrig did. Although it disappointed his mother to see him drop out of school, both of Gehrig's parents were ill at the time and the family desperately needed the money.