It’s easy to forget that Brees spent five seasons with the Chargers before he joined New Orleans. He set dozens of passing records during his time in the Big Easy while his time in San Diego was average. In 2005, the Chargers hoped to improve on their 12-5 record but fell short of the playoffs.
Brees had a labrum injury that curtailed his season and this hurt their chances of a postseason run. They won some huge games but ultimately didn’t make it to the promised land. Meanwhile, it gave Philip Rivers the chance to stake his claim and he became their new long-term starter (via Firstsportz).