Harris committed to the University of Alabama to play college football under head coach Nick Saban.

With Henry leaving for the NFL, Harris became Alabama's starting running back in 2016, beating out Bo Scarbrough.

[5] In the third game, against Ole Miss, Harris carried 16 times for 144 yards, including a 67-yard run in which he out-muscled two defenders.

[6] A sprained knee against Kent State on September 24 caused him to sit out the rest of the game,[7] but he returned the following week against Kentucky.

[12] He made his professional debut in the team's Week 7 33–0 victory over the New York Jets, rushing for 12 yards on four carries.

[18] In Week 10, Harris rushed the ball 22 times for 121 yards, both career highs, helping lead the Patriots to a 23–17 upset victory over the Baltimore Ravens on Sunday Night Football.

He was mostly ineffectual, however, during the Week 3 and 4 losses against the New Orleans Saints and the Tampa Bay Buccaneers respectively, being held to only 10 total yards rushing combined between the two games.

A hamstring injury suffered in Week 5 slowed down his production and allowed Stevenson to overtake him as the lead back, but still split carries with the second-year player.

[26] Harris scored his first touchdown as a Bill during a 38–10 Buffalo win against the Las Vegas Raiders in week 2.