He played college football for the Utah Utes,[1][2][3] earning first-team All-American honors in 2014.

He was selected by the Tampa Bay Buccaneers in the sixth round of the 2015 NFL draft.

[4] He caught 20 passes for 502 yards and six touchdowns in his junior season on a team that won the Southern Section title.

He began his SuperPrep All-American and All-Moore League senior season as a wide receiver before moving to the backfield for the final four games.

On November 8, 2014, Clay received national coverage when, with Utah up 7–0 against the Oregon Ducks, on what would have been Clay's defining 79-yard touchdown for his collegiate career, he celebrated prematurely and dropped the ball on the 1-yard line, allowing Oregon's Joe Walker to recover the ball and return it 99 yards for a touchdown in the opposite direction, changing the potential 14–0 score to a 7–7 tie; Oregon would go on to win the game 51–27.

[8][9] The Tampa Bay Buccaneers selected Clay in the sixth round of the 2015 NFL draft with the 184th overall pick.

[23] On September 2, 2017, Clay was traded to the Buffalo Bills for cornerback Kevon Seymour.

On December 22, 2018, Clay signed with the Salt Lake Stallions of the Alliance of American Football.