Farrell was drafted by the Jacksonville Jaguars in the fifth round, 145th overall, of the 2021 NFL draft.[5] He signed his four-year rookie contract with Jacksonville on May 20, 2021.[6] Farrell played in all 17 games for the Jaguars during the 2021 season, catching his first pass during a Week 2 13–23 loss to the Denver Broncos. He finished the season with seven catches for a total of 56 yards and no touchdowns. His longest reception was 21 yards, during a Week 6 23–20 victory against the Miami Dolphins.