4. Retirement
This is complete speculation and all in how Kirk Cousins views the next stage of his career. The quarterback could choose to walk away. Those who have spent so many years as a top starter in this league struggle to adjust to age. While Cousins still could turn back into the player we saw at the start of the season all options have to be explored.
Cousins could simply be dealing with an injury and still be a franchise quarterback. It wasn't long ago we watched the veteran set the single game franchise passing record and light up the Tampa Bay Bucs. This was who the Falcons believed was going to be their quarterback moving forward.
If that version of Cousins is able to be found in the last games of the season the veteran will have a job in Atlanta or his pick of landing spots. However, if the player we watched against the Chargers is who Cousins will be moving forward you're a backup in this league. No matter what the Falcons are paying you that level of play will not be given another chance to start. If that is the case, could the quarterback entertain walking away if starting is no longer an option?