Gailey has now had three years to prove he is the answer in Buffalo, and he and his quarterback, Ryan Fitzpatrick, have done nothing to prove they deserve to stay.
A change is needed in Buffalo: The team is playing uninspired football and Gailey's decisions are shockingly bad (such as giving star running back C.J. Spiller only seven carries in a game).
The most recent example of futility in Buffalo came Sunday when the Miami Dolphins beat up on the team 24-10.
It is clear things are over for Gailey, but what is next for the franchise? Let's take a look at five candidates the Bills organization should consider this upcoming offseason.
Shanahan is in line for a promotion purely based on his outstanding work with Redskins rookie quarterback Robert Griffin III. He built an offense directly around RG3's skill set, and it has worked to perfection this season.
With Shanahan at the helm of the Bills, he could build another stellar offense around a soon-to-be-drafted rookie quarterback. He is unproven on defense, but at this point, the Bills will take anything they can get.
In the face of adverse conditions, Bruce Arians has done a miraculous job as interim head coach for the Indianapolis Colts this season.
Arians had never received a head-coaching shot before this year, but seems to fit the role just fine. He's a hard-nosed coach who gets the absolute most out of every player on his roster.
In essence, he's the anti-Chan Gailey.
Arians may not be interested in a head-coaching position, especially with Buffalo, but that doesn't mean the Bills shouldn't try.
Horton has the Cardinals playing at a borderline elite level despite the lack of outstanding talent. He's in line for a head-coaching position given his impressive pedigree and performance.
Buffalo is the perfect landing spot for a man like Horton. The organization needs a culture change, and Horton comes from a winning one. Horton could easily turn the Bills into a defensive powerhouse while guiding it through a rebuilding mode.
While mentioning defensive masterminds, it would be a criminal offense to not bring up Dom Capers, who currently acts as the defensive coordinator for the Green Bay Packers.
Capers has been around for what seems like forever. He has guided expansion teams such as the Carolina Panthers and Houston Texans to some success, so helping rebuild the Bills would not be an issue.
Buffalo needs a lot of help, and Caper has what it takes. His countless years of experience and proven track record make him more than a suitable candidate for the job.
The only issue at this point is if Capers still wants a head-coaching position. If so, he is an ideal fit in Buffalo.
Mike Zimmer has built himself quite a stellar reputation as the defensive coordinator of the Cincinnati Bengals.
Zimmer has consistently turned a once-mediocre unit into an elite unit because he excels at placing his players in a position to succeed. The Bengals have not had a bad defensive unit since Zimmer's arrival, which makes him a prime candidate for a head-coaching position.
While Zimmer does not have as much experience as some of the other candidates the Bills could bring in, that is what makes him such an appealing option.
Zimmer is waiting for the right team to give him a chance, and then he can begin to build his legacy as a head coach. He's strict, but allows his players to succeed.
There's not a better candidate for the Bills this offseason, and part of the reason is Zimmer would actually consider coaching in Buffalo.
Buffalo needs to interview Mike Zimmer.