2. Johnny Unitas, 40 in 1973
Johnny Unitas joining the Chargers is one of the most forgotten about things in NFL history. Unitas was the best quarterback of all time by the time he hung it up after the 1973 season and his records are still among the best to ever do it almost 50 years later.
Unitas is undoubtedly still one of the greatest quarterbacks of all time for what he accomplished in his era. His longevity was unmatched until today's era of quarterbacks started to test father time as he played 18 seasons in the league.
All but one of those seasons were with the Baltimore Colts. Unitas was a three-time MVP, three-time NFL Champion and one-time Super Bowl Champion with the Colts. Then he was traded to the Chargers prior to the 1973 season.
Tom Brady won a Super Bowl with the Tampa Bay Buccaneers, Peyton Manning won a Super Bowl with the Denver Broncos. Heck, even Brett Favre made an NFC Championship game with the Minnesota Vikings.
Unitas only played five games for the Chargers in 1973 despite signing a two-year contract. He played terribly in those five games and was ironically replaced by none other than Dan Fouts.