 On December 24, 2017, Bethea made three solo tackles, two pass deflections, and intercepted two pass attempts by Eli Manning in a 23–0 win against the New York Giants in Week 16.On December 26, 2017, the Arizona Cardinals placed Bethea on injured reserve after he tore his pectoral a muscle in Week 16.He completed the 2017 season with 57 combined tackles (47 solo), nine pass deflections, a career-high five interceptions, and a sack in 15 games and six starts.