Because he felt like it?
Mantle played from 1951 to 1968.
Mickey Brantley debuted on August 9, 1986 and played his final game on June 1, 1989.
Mickey Cochrane debuted on April 14, 1925 and played his final game on May 25, 1937.
Mickey Corcoran debuted on September 15, 1910 and played his final game on October 9, 1910.
Mickey Devine debuted on August 2, 1918 and played his final game on September 26, 1925.
Mickey Doolin debuted on April 14, 1905 and played his final game on September 2, 1918.
Mickey Mantle was an all-around athlete at Commerce High School, playing basketball, football, and baseball. On April 17,1951 Mickey Mantle made his Major League debut with the New York Yankees.
Mickey Mantle first tried to play the baseball position of shortstop. He believed he did not the timing required to play this position. He found himself making too many errors.