On November 16, 2020, following the dismissal of former head coach Will Muschamp, Horn opted out of the remainder of the season, turning his focus to preparation for the 2021 NFL draft.

[13] Throughout training camp, Horn competed to be one of the starting cornerbacks against veterans Donte Jackson and A. J. Bouye.

Head coach Matt Rhule named Horn and Jackson the starting cornerbacks to begin the regular season.

In Week 2, Horn recorded his first career interception off Jameis Winston against the New Orleans Saints in the 26–7 win.

[14] In Week 3 during their 24–9 win against the Houston Texans, Horn suffered a fractured foot and was placed on injured reserve on September 27.