 Wilhelm was one of eleven children born to poor tenant farmers John and Ethel ( née Stanley ) Wilhelm in Huntersville , North Carolina . He played baseball at Cornelius High School in Cornelius , North Carolina . There , he began experimenting with a knuckleball after reading about pitcher Dutch Leonard . He felt that , because he could not throw fast , honing a knuckleball offered him his best shot at success . He used a tennis ball to practice . 
