Franchises on the fringe are beginning to ponder change.
Change at the very top, where hand-picked coaches of old have worn out their welcome with finicky owners bearing a wandering eye for the next big hire.
It's an ugly time of year for embattled staffs who can feel the weight of impending group dismissals in the mail. On the opposite end of the spectrum, though, a handful of high-flying head coaches and coordinators are seen within team walls and beyond as the very reason their teams are angling toward January play.
The best of these leaders find a way to keep their squads chugging through Thanksgiving before peaking at just the right time.
As December dawns, here's my (utterly impregnable) list of which coaches matter most in a critical slate of Week 13 action:
1) Texans coach Bill O'Brien: He doesn't get enough credit. Veering toward his fourth winning season in five years, O'Brien has the Texans soaring off eight straight wins. Their Monday night smacking of the Titans was a thing of beauty and the team's finest outing all year, but Sunday presents another thorny to-do.
In the middle of a three-game homestand, the Texans (8-3) welcome the Browns (4-6-1) to town, a happy scenario in years gone by made less inviting by the presence of Baker Mayfield. Cleveland's rookie quarterback is coming off two encouraging showings, but it's fair to note he shone bright against a pair of junky defenses from Atlanta and Cincinnati. Still, this Browns team has young talent on both sides of the ball and hits the scene with a devil-may-care attitude after being left for dead when Hue Jackson was canned in late October. The Browns are an unpredictable bunch with an undefinable ceiling.
The Texans bring something different to the table, though, with a frenetic, punishing defensive front led by supermen J.J. Watt and Jadeveon Clowney. While the Browns have kept Baker safe of late -- no sacks in two weeks -- the less-than-golden tackle combination of Greg Robinson and Chris Hubbard will have their hands full from wire to wire. With the surging Colts heading to Houston in Week 14, it's up to O'Brien to prevent a letdown as the Texans keep their bye hopes afloat in the AFC.
2) Bears frontman Matt Nagy: Speaking of eyeing a first-round pass in the playoffs, Chicago (8-3) isn't out of the mix. It's tough to imagine the Saints or Rams falling apart down the stretch, although New Orleans hit a snag on Thursday night. The Bears can hope against hope for one of those juggernauts to falter while taking care of their own business.
That business in Week 13 is a homely, lost ghost-ship named the New York Giants. No reason for a setback -- not with so much on the line for this lovable Bears cadre. Nagy has performed Coach of the Year-level work in his first campaign and currently rides a five-win streak that's seen Chicago carve out a plus-70 point differential and plus-seven turnover mark while the rest of the NFC North attempts to get its act together.
What I love is the consistency. You see a similar Bears team week-to-week, which even held true with Mitch Trubisky out of the lineup against Detroit. With backup Chase Daniel expected to start once again, Nagy must spin his magic before a rugged two-game stretch with the Rams -- there's your shot to upset the apple cart -- and Packers.
3) Steelers defensive coordinator Keith Butler: When Pittsburgh (7-3-1) hosts the Chargers (8-3) on Sunday, the stakes are clear. A loss for the Steelers could feasibly put them two wins behind Los Angeles, Kansas City, New England and Houston in the derby for an AFC bye.
The challenge for Butler is crystal-clear: Keeping a lid on a Bolts attack that saw ageless wonder Philip Rivers rattle off 25 straight completions against the Cardinals while etching his 12th straight tilt with two-plus touchdown strikes.
The Chargers won't be the same with MCL-addled running back Melvin Gordonout of the mix, but backup Austin Ekeler is no slouch, averaging more yards per touch than Gordon (7.5 to 6.4) and leading all players with one-or-fewer starts in rushing (409) and scrimmage yards (763) in 2018. The Steelers know plenty about a backup runner making the leap in a big spot.
Besides, it's not just Ekeler. With Gordon in and out of the lineup against Arizona, the Chargers also milked saucy production out of rookie Justin Jackson. This offense is deep, explosive and able to score in spurts, but the Steelers -- with the attention so often focused on Big Ben and friends -- field the NFL's third-ranked scoring defense since Week 5, which during that span has allowed fewer yards per game than any team around. Quarterback chasers T.J. Watt and Cameron Heyward have combined for 16 sacks while versatile defensive back Mike Hilton is an unheralded gem who helps make the secondary click. This is the premier matchup of Week 13.
4) Colts coach Frank Reich: Look no further than Philly for evidence of what Reich brings to the table. The vanilla Eagles certainly seem to miss their old offensive coordinator, who was integral in crafting the team's Super Bowl game plan against Bill Belichick's Patriots.
Nine months later, Reich has the Colts operating as one of the hottest teams league-wide. Their 6-5 record pegs them just outside the playoff invite list, but the Colts are a classic tale-of-two-seasons operation, ripping off wins in their last five games to the tune of 34.6 points per tilt. That juicy production is the product of a front five that's allowed only one sack since Week 6. The upshot? Andrew Luck sits on pace for career marks in almost every relevant metric for an NFL passer.
Up next: the floundering Jaguars, a team seen in September as a Super Bowl contender, but now reduced to a pile of salt with a benched quarterback, fired offensive coordinator, stumbling defense and smatterings of touchy in-fighting. The Colts face tricky upcoming tilts with the Texans, Cowboys and Titans, so knocking out the walking-dead Jaguars is a must.
5) Embattled Packers coach Mike McCarthy: He's been there so long, it's awkward to imagine anyone else but McCarthy on Green Bay's sideline. Too many of his 13 seasons with the Packers, though, have ended in ghastly disappointment -- an unforgivable sin due to the presence of a from-the-stars passer in Aaron Rodgers.
McCarthy's offense remains stuck in neutral while the league is watching creative schemes bloom from east to west. With just two losing seasons since 2006, there's no question McCarthy is a competent leader, but he finds himself firmly on the hot seat because this year's team simply can't get out of its own way.
While every coach yearns for a talent like Rodgers, his presence seeds new layers of pressure. Anything less than annual trips to the Super Bowl feels entirely unacceptable. That explains the outrage over a four-win team resembling a figure creeping around in the dark hunting for the light switch -- one that should have been flipped weeks ago.
Follow Marc Sessler on Twitter @marcsesslernfl. Listen to Marc on the "Around The NFL Podcast" three times a week.
