In 1949 Mickey Mantle was just another minor leaguer making his professional debut with the Class D Independence Yankees. The future Hall Of Famer batted .313 in 89 games that season. Jack Brownlee was six years old that season when he had Mantle sign his Independence Yankees program. In the story link below which includes a video, you can see the autograph and here Brownlee tell the story of obtaining it in the small Kansas town.
Leesburg man sells Mickey Mantle autograph — WALB.com