This means another new defensive coordinator for the Broncos.
The success was short-lived for Denver, and they'll need to pick up the pieces and rebuild again on the defensive front.
Allen made a Denver defense that ranked dead last in almost every major category in 2010 into something respectable in 2011.
While everyone watched the drama of the Tim Tebow-mania unfold on every nightly newscast and every morning sports show, Allen quietly formed this defense behind the scenes.
The Raiders score their ninth head coach since the team moved back from Los Angeles in 1995.
What does it mean for the future of these two franchises?
Allen provides a slight edge for the Raiders in their two matchups with the Broncos each year, as he'll have a wealth of knowledge about how a Tebow-led offense functions against a defense.
On the other hand, the Broncos know how Allen works, and may hold a card or two up their sleeve when battling their defense twice next season.
The suitors will hopefully come calling soon for Denver as the opportunity to coach a sack-master like Elvis Dumervil, a veteran hero like Champ Bailey and one of the most exciting young defensive players in the league in Von Miller is now a viable option for unemployed coaches looking for work.