Philip Rivers has come out of retirement to rejoin the Indianapolis Colts, five years after the 44-year-old grandfather last played in the NFL. The Colts faced a sudden need to fill their quarterback room after picking up two injuries during Sunday's 36-19 loss to the Jacksonville Jaguars. Back-up quarterback Anthony Richardson was already out with a facial injury, so Rivers worked out for the Colts on Monday - his 44th birthday. That makes Rivers the oldest current player in the NFL, surpassing Pittsburgh Steelers quarterback Aaron Rodgers, who turned 42 last week. Colts head coach Shane Steichen served as offensive coordinator and quarterbacks coach while Rivers was with the Chargers.