Sanders led the AAFC in rushing yards and was named All-AAFC in 1946 and 1947. In 1947 Spec led the AAFC with 231 carries, 114 points, and 18 rushing touchdowns, a new pro record that stood until Jim Taylor broke it in 1962. Spec’s 1,432 rushing yards established a mark until 1958, when Jim Brown ran for 1,527 yards. Spec completed 93 passes for 1,442 yards, adding 14 more touchdowns to the team’s total. He also returned a kickoff for a score. Although he was used sparingly on defense, Spec intercepted three passes. He also averaged 42.1 yards on 46 punts. The Professional Football Researchers Association named Sanders to the PRFA Hall of Very Good Class of 2008 
Spec’s greatest game that year came on a Friday night in October against the Chicago Rockets. He carried the ball 24 times and gained 250 yards to set a pro record that was not touched for more than 25 years. He was removed from the game after only three quarters.
Sanders suffered from knee woes and retired after the 1948 season. Despite this, he finished as the AAFC's second leading all-time rusher and all-time leader in rushing touchdowns. He was lured out of retirement to play in the NFL in 1950. Because of the knee problems, he opted to play only defense that year. He responded by being named to the Pro Bowl and tying the NFL's all-time single season interception record. At that point, Spec Sanders decided to retire for good.