Mandley was a two-time first team All-America and two-time honorable mention All-America at NAU. Mandley was selected in second round by the Detroit Lions in 1984. He played in the NFL for eight years. At one time he held the NCAA I-AA career record for all-purpose yards with 5,925, a mark which still stands as the NAU and Big Sky Conference record at the time of his induction. In addition to career all-purpose yards, Mandley also established NAU career records with 1,988 kick-off return yards, 901 punt return yards, 3 punt returns for touchdowns, and 26 total touchdowns, all records which still stand at the time of his induction.