Terrell Davis
The Broncos entered a transitional period in 1999 because John Elway retired. It was always going to be a big ask to succeed with a new quarterback after so long with their franchise icon at the helm. Davis had a significant role to play in their hopes of success but ultimately he sealed their doom.

That’s because his ACL tear came out of nowhere in the fourth week of the season. The Broncos proceeded to lose a string of games by seven points or less without their elite running back. That was the end of their playoff hopes because they didn’t have the talent to replace him (via Sportskeeda).