There are lots of reasons teams fail over the course of an NFL regular season. Injuries play a key role in how things unfold across the league, but every loss suffered by a club can't be excused away with an injury report -- as some of the better coaches usually scheme to adjust for such absences, which includes building a roster and coaching staff that can withstand the inevitable bite of the injury bug itself. Additionally, there are clubs who are faring better than most others in that regard, and yet still find themselves sliding into oblivion as the weeks roll along.

In the end, the onus will always fall back onto the lap of the respective head coach, and several find themselves on the hot seat heading into Week 15, many being familiar to having a heated bottom over the last few weeks and/or months. There's been movement, however, with some seeing their chair cooled a bit, while others simply poured more gasoline on the embers beneath them. And then there's Mike Tomlin, who finds himself removed from the list altogether after mounting an 8-5 record despite now operating with a third-string quarterback, having led the Pittsburgh Steelers to wild-card contention in the process.

Tomlin is amazing, and his seat could not be more ice cold, but the same can't be said for others on this list.

No one else has earned such a respite from the hot seat rankings, and using the U.S. military DEFCON readiness scale -- in honor of NFL's "Salute to Service" -- let's take a look who sits where.

DEFCON 5: Safe ... for now

12. Jason Garrett - Cowboys

Faced with a 3-3 start after dropping three straight games that included a loss to the hapless New York Jets, Garrett's seat was white hot heading into Week 7. He went on to helicopter drop volumes of water onto it when he led the Cowboys to a dismantling of the Philadelphia Eagles, and enjoyed further cooling by climbing back from a slow start to pick apart another rival in the New York Giants, garnering two needed wins in two weeks that also happened to be against division foes. Things seemed back on track, but then came the Minnesota Vikings after scraping past the Detroit Lions, and then a mistake-laden loss to the New England Patriots led to owner Jerry Jones railing against his own special teams and coaching staff. 

Four days later, they got molly-whopped by the Buffalo Bills at home on Thanksgiving. Still, as I've long reported, there will be no firing of Garrett in 2019.

As long as the Cowboys are atop the NFC East and in the playoff picture, Jones will not fire him, but what the team does in January will determine if Garrett lands a new contract in 2020. So, why's he on this list? It's because he deserves to be.

11. Freddie Kitchens - Browns

If you want a lesson in how to escape a minefield, Kitchens could probably teach you, as he lands the honor of my biggest mover and shaker on this list. The Browns were on a six-game losing streak and again the laughingstock of the entire NFL, leading to Kitchens initially being as high as DEFCON 2, considering how massively underwhelming his high-powered stable of talent had become in his first season as head coach in Cleveland.

Now winners of four of their last five -- including over the Buffalo Bills -- it feels like the tide is beginning to turn for Kitchens and Co. That presumption will be tested in a big way over the course of their remaining few games, as they sit at 6-7 on the season and not yet eliminated from playoff contention. If Kitchens can continue to mount the forces, the Browns will go on to deliver the biggest turnaround in the NFL this season, and his job will be safer than money in a mob vault.

He'll have to do it without All-Pro pass rusher Myles Garrett, and that will only make things more challenging but, at least for the moment, Kitchens has his critics taking pause. The ground he stands on remains filled with land mines, though.

The Patriots are involved in another controversy and there's a lot to go over. Brady Quinn and Ryan Wilson join Will Brinson to break it down, along with culture issues in Cleveland, the 2020 draft and more. Listen below and be sure to subscribe for daily NFL goodness.

10. Matt Nagy - Bears 

Nagy can exhale a bit at the moment, with the Bears ending their four-game losing streak and having now won two straight and four of their last five games. That's quite the turnaround for Nagy in Chicago, and it's why Nagy saw his seat cool noticeably over the past few weeks after continually hitching his wagon to the inconsistencies of Mitchell Trubisky. Well, the marriage is flourishing as of late, with Trubisky pulling Nagy out of the flames the past few weeks, putting him on much more solid ground as the regular season nears its conclusion. 

There's still much work to be done, and the Bears will also need help from other teams if they're going to sneak into an NFC wild-card seat -- something that's still unlikely to occur -- but the future looks much better for Nagy than it did a month ago. Unless the Bears collapse and lose their next three games, which is possible considering they're up against the Packers, Chiefs and then Vikings, Nagy can use his second-half turnaround to argue for another shot in 2020.

Should that collapse occur, however, it'll be a much different conversation in the front office.

DEFCON 4: Danger lurks

9. Kliff Kingsbury - Cardinals

Things got fun for a little bit in Arizona, when the team went on a three-game win streak after beginning the year 0-3-1, but they're back to their losing ways and Kingsbury finds himself still fighting to figure out what type of team the Cardinals need to be to become contenders. That won't happen in 2019 though, after losing six straight -- their second-longest losing streak of 2019 -- to fall to 3-9-1 and far out of the playoff picture. 

That's not what the Cardinals envisioned when they wooed Kingsbury to the NFL and shipped away Josh Rosen to select Kyler Murray with the first-overall pick, and although Kingsbury will likely be given space to make errors in 2019 -- which is why he won't find himself unemployed in the next few minutes -- a continued collapse could change his fate once the season concludes or, at minimum, one or two assistants to help reset for 2020.

It's highly unlikely Kingsbury gets canned in 2019, hence his position at No. 9 on this list, but his record this year can't be ignored.

8. Adam Gase - Jets

All it took was a defeat of the also unimpressive New York Giants to secure Gase's job, with team owner Christopher Johnson stating unequivocally there would be no changes at the head coach position in 2019. Johnson is clear that Gase will return for 2020 and, knowing that, you're now wondering why the first-year Jets head coach is still on my list. Well, it's because owners can say whatever they like on Wednesday, and do the exact opposite on Saturday.

Sam Darnold showed serious regression prior to the Jets winning four of their last five games, but credit Darnold and Gase for weathering the hurricane to get things turned around. Still a wildly inconsistent team that has shown they can defeat a team like the Raiders, but also lose to the Dolphins, and a new crop of player controversy has now found its way to Gase's locker room -- as has been the case at several points this season. It's incumbent for Gase to not only finish the year strong, but to also get a handle on his locker room, before it all pushes him right back into DEFCON 1 -- be it now or in 2020.

Kudos to Gase for earning a more "safe" place on this list, but let's not pretend he's no longer in danger. He's bought himself more time with Mr. Johnson, but don't go pulling him out of the fire yet.

DEFCON 3: At the ready

7. Vic Fangio - Broncos 

Speaking of turnarounds, the Broncos are enjoying one at the moment, and Fangio could not be more relieved. Things have gone from promising before the season, to worrisome at the outset, to an absolute tailspin with only five regular season games left to play, to the Broncos and rookie Drew Lock rattling off two straight -- including an obliteration of the AFC South-leading Texans in Houston. Fangio was brought in this year to replace Vance Joseph, who himself was fired after a short stint as head coach, and the hiring came attached to a decision by John Elway to trade for Joe Flacco; and that was supposed to finally resolve the ongoing uncertainty at quarterback while providing a steady and fiery hand at the helm in Fangio. 

It didn't, but Lock has, and seemingly in a big way. The presence and play of Lock makes for an intriguing consideration going forward regarding Fangio, who has seen his play calling brought into question often this season, but is now finding a way to string together wins with Lock under center. There's still a lot to figure out in Denver in the immediate and long-term, but Fangio has stepped back from the precipice of disaster and -- even if only for a moment -- made the Broncos fun again.

His ability or inability to lengthen that moment will determine what John Elway chooses to do next. 

6. Anthony Lynn - Chargers

Speaking of Lock, Lynn and the Chargers were on the losing side of the rookie's first career win in the NFL, made worse by the fact he was on injured reserve the entire season before taking the field to take down Los Angeles in Week 13. Just when you thought the Chargers were ready to mount a run in the second half of the season, they remind you time and again they weren't. Lynn has done a great job of overcoming the loss of several star players this season, all things considered, going so far as to galvanize the team into defeating the Bears in Chicago and flat out knocking the teeth out of the Packers in Week 9. 

That's a testament to the grit and leadership of Lynn, which was on full display when he opted to not re-attempt a field goal against Green Bay with the opportunity to extend the lead by three points; but instead deciding to run it down their throats for a touchdown that sealed the coffin closed. That now feels like forever ago, as poor play from Philip Rivers leaves Lynn with a decision to make in the near future, and the Chargers with one to make on Lynn. 

The decision to fire Ken Whisenhunt helped momentarily, but without that scapegoat, it might be Lynn now put out to pasture.

5. Dan Quinn - Falcons

Although he didn't enjoy as much movement on this list as Kitchens, Quinn has escaped DEFCON 1, and that's saying something. Yes, he recently lost to the Tampa Bay Buccaneers, but he also coached a masterful performance in Louisiana to down the New Orleans Saints before then heading to Charlotte to dismantle the Carolina Panthers -- serving notice the Falcons won't lay down, and that Quinn hasn't lost the locker room. Winners of three of their last five games, they're a dangerous spoiler for anyone facing them in December. Going on to sweep the Panthers only makes things that much more cozy for Quinn, although he's still not removed entirely from the danger of a potential mind-change from owner Arthur Blank.

Blank has been consistent in his defense of Quinn and it's paid off as of late, yes, but the fact remains the Falcons won't participate in the playoffs for a second straight season, and only three seasons removed from their historic Super Bowl appearance and collapse. The fall from grace isn't being ignored by Blank, no matter what he might have the media believe, but Quinn has bought himself a bit more time and at least a fruitful dialogue with Blank thanks to their December record.

It's a chapter that provides hope for the future, but the other chapters in this book can't be ignored.

DEFCON 2: Mobilize the forces

4. Zac Taylor - Bengals

Another week, another loss for the Bengals, but at least they finally landed their first win to avoid going 0-16, right? It's a sad day when garnering a single win in three-fourths of an NFL season, and against the New York Jets, can lead to elation in a fanbase, but it reveals just how bad the Bengals have been in the first year under Taylor. To make matters worse for Taylor, they didn't even put up a fight against the Baltimore Ravens, who roundly trounced them in Week 10 with a 49-13 shellacking that saw Lamar Jackson pull out video game moves on them; and they've since mustered only 10 points per game in losses to the Raiders and Steelers. There is nothing to be hopeful for in Cincinnati, having benched a disgruntled Andy Dalton -- who skewered the club for not giving him a chance to find a trade suitor -- only to now rename him starter after rookie Ryan Finley went 0-3 at the helm.

It's uncertain what Taylor's goal is with the reinsertion of Dalton, other than not going 0-16, but it might really be as simple as that; although it's clear Dalton is now auditioning to find a way out of Cincinnati. Meanwhile, Taylor is doing all he can to audition to remain there, but all he can sell to ownership right now is a plan for the future with no evidence to support it. His first season with the Bengals has been an unmitigated disaster, period.

The team might not give up on him quickly, but no one would blink if they did.

3. Matt Patricia - Lions

There was a ton of excitement surrounding the hiring of Patricia in Detroit in 2018, but all of that is officially out of the window. In his first year with the club, he struggled through first-year head coaching adjustments, growing pains and issues as the team stumbled into a 6-10 finish and no playoff appearance. Dismissed as just that -- a first-year learning curve -- Year 2 hasn't gone any better, and in fact has been worse, leading many to wonder if there will be a Year 3 in this regime. The Lions are 3-10 and a team still in contention for the NFC North back in October has seen the wheels come off and roll down the road without the rest of the car attached to them. 

Losers of their last six games, a streak that began before Matthew Stafford was sidelined with fractures in his back, it's time to discuss the future of Patricia. He holds firm he has no concerns about his status with team going forward, but that feels more like simply the right thing to say publicly than a true belief on his part. Blame the absence of Stafford, sure, but the Lions were still sub-.500 (3-4) this season with Stafford at the helm.

So, maybe the issue runs much deeper than the quarterback, hmm?

2. Doug Marrone - Jaguars

Remember when watching the Jaguars was fun this season? It was a magical time that saw rookie Gardner Minshew step in for an injured Nick Foles and have his way with the league, but that rollercoaster fell off the rails a while ago. Foles was reinserted into the starting role once healthy and after the magic of Minshew died, but the wins didn't return. With losses mounting, Marrone then placed Minshew back in the lineup but, you guessed it, the wins have still yet to return. In the end, this season will mark the second in a row in Marrone's three-year tenure with the Jaguars wherein they've not made the playoffs, and it's highlighted by a sideline argument with All-Pro cornerback Jalen Ramsey that led to team exec Tom Coughlin and owner Shad Khan shipping him to the Los Angeles Rams.

It's not something Khan truly wanted to do, but felt it prudent to side with Coughlin and Marrone in the matter. Clearly, however, the Ramsey dilemma was not the [only] problem within the organization, and now Marrone finds himself on the chopping block as the offseason approaches. The same goes for Coughlin, who will likely be more than willing to sacrifice Marrone to save his own hide.

However you slice it, Marrone may not be employed in North Florida much longer.

DEFCON 1: Fire [him]

1. Pat Shurmur - Giants

Good grief, Charlie Brown.

The Giants lost six straight games heading into their bye week, and took the additional time to sort things out so they could go on to lose a seventh in Week 12. Things only continued to tailspin from there, culminating in the return of Eli Manning -- due to injury to Daniel Jones -- against the Philadelphia Eagles after blasting off to a 17-3 start at Lincoln Financial Field on "Monday Night Football," only to suffer a 23-17 loss in overtime after leaving Zach Ertz wide open in the end zone for the walk-off touchdown. They now sit at 2-11 on the year and zero hopes of doing anything more than playing spoiler going forward, but Shurmur and the Giants can't even do that right. 

The decision to bench Eli Manning for Daniel Jones paid off initially, but Jones is now playing very much like a rookie and All-Pro running back Saquon Barkley is basically a shell of himself in Shurmur's scheme, while having not eclipsed the 100-yard rushing mark since Week 2. Barring an explosive finish to the season that sees the All-Pro averaging 130 rushing yards per game, he'll end the year below the 1,000-yard mark only one season after eclipsing 1,300 yards on the ground. He's also on track to produce less than half of his receiving yardage tally from 2018 but, to put it plainly, there's nothing wrong with Barkley.

There is, however, everything wrong with Shurmur.

The club is now 7-22 in his tenure, with many more losses to come unless the Giants and general manager Dave Gettleman -- who himself is in danger of being fired -- oust him. For an organization that had a lot of success under longtime head coach Tom Coughlin before moving on to Ben McAdoo, who then led the Giants to the playoffs in his first year, Shurmur is fumbling an opportunity to truly dig his heels in at the post. New Yorkers are notoriously not the most patient bunch, nor should they be, when the head coach of their favorite team has nearly three times the number of losses as wins. Of all NFL head coaches who have coached at least 60 games, only two men in NFL history have had a worse record than Shurmur.

Shurmur should've been fired weeks ago, which is ironically further evidence Gettleman should get the ax as well.