Duckett was a consensus prep All-America at Loy Norrix High School in Kalamazoo, Michigan, where, as a senior, he was named "Parade" magazine and Rivalnet National Player of the Year. In addition to running back, he played linebacker and quarterback. As a junior, he had 140 tackles, three sacks and two interceptions and accounted for 2,080 total yards and 20 touchdowns on offense. He was named Defensive Player of the Year by Prepstar, SuperPrep and Rivalnet. As a senior, he rushed for 1,623 yards (11.2 avg.) and had 21 touchdowns. On defense, he recorded 102 tackles, nine sacks, and forced four fumbles. As a quarterback, he threw for 920 yards and nine touchdowns.