Johnny Unitas
There’s a strong argument to be made that Unitas was the first great modern quarterback. The 10-time Pro Bowler won NFL Championships and a Super Bowl during his glittering career with the Colts. It’s almost unfair to mention that final season in San Diego (via Retro Seasons).

He spent 17 years in Baltimore before he decided to try something new instead of retiring. There’s still something wrong with Unitas wearing a Chargers uniform. Furthermore, his form immediately plummeted and he only lasted for a season in California before he retired.