15. Philip Rivers
At one point in time, Philip Rivers was such a promising quarterback prospect that the San Diego Chargers were comfortable enough to part ways with Drew Brees. In his first four seasons as the starting quarterback of the Chargers, Rivers went 46-18, and San Diego advanced to the divisional playoffs four years in a row. But, one way or another, they kept finding a way to suffer defeat after defeat.
Rivers has made the Pro Bowl eight times in his highly successful NFL career to date, and currently ranks 8th on the all-time passing leaders list.