Rivers played his first game with the Colts on September 13, 2020, finishing with 363 passing yards, one touchdown, and two interceptions as the Colts lost 27–20 to the Jacksonville Jaguars. He earned his first victory with the Colts in a Week 2 28–11 victory over the Minnesota Vikings. He passed for 371 yards, three touchdowns, and one interception in the 31–27 victory over the Cincinnati Bengals in Week 6, which he led the Colts back from down 24–7. In Week 8, against the Detroit Lions, Rivers threw for 262 yards and three touchdowns in a 41–21 win.