Because of their success over the past 16 seasons, there haven’t been a lot of occasions where poor performance forced a Patriots coaching shakeup.  

It takes a gargantuan meltdown for them to give a coach the gate. Sunday’s work by the Patriots offensive line qualified.

As we reported Monday night, offensive line coach Dave DeGuglielmo’s head rolled after the Patriots 20-18 loss in Denver on a day when Tom Brady took about two dozen hits and the offensive line was non-competitive.

The last time the team moved quickly to replace a coach after a unit went bellyup was when defensive coordinator Dean Pees was let go following the team’s 33-10 loss to the Ravens in the 2009 playoffs.

As in Pees’ case, there are extenuating circumstances that might leave DeGuglielmo feeling like the fall guy.

Injuries – specifically the loss of left tackle Nate Solder – caused a musical chairs routine up front that had the Patriots at less than their best in terms of firepower from Week 5 on. Meanwhile, DeGuglielmo was the guy who coached up a group that had three rookie starters on the interior – left guard Shaq Mason, undrafted center David Andrews and right guard Tre Jackson – for a good chunk of the early season when the Patriots were dominant. How could he be deserving of a pink slip? And when you construct an offense that is so one-dimensional and arrange it so that the running game is an afterthought, it’s going to look ugly when a opponent has a great day in the pass rush and in coverage.  

But those circumstances are fine print compared to the failure writ large against the Broncos.

Sunday’s performances by Marcus Cannon, Sebastian Vollmer, Josh Kline and Bryan Stork (Mason wasn’t a disaster) were so disjointed, so bereft of any feeling that the O-line was five fingers working together on the same hand that there had to be fallout.

You can’t fire the players. At least not all of them. You can, however, make a move that indicates how wholly unacceptable Sunday’s performance was. That’s what this move did.

It wasn’t all about Sunday and nearly getting Brady sawed in half, either.

DeGuglielmo followed a Patriots coaching legend, Dante Scarnecchia, when he was hired prior to 2014 after Scarnecchia’s retirement.

There were a few occasions during that first training camp where I asked offensive linemen about the new coach and they’d answer with a hesitant, “It’s different…” and leave the rest unsaid.

DeGuglielmo was a little more rah-rah than Scarnecchia, who had a drill sergeant’s demeanor. And while that shouldn’t pose a particular problem, players did seem slow to warm to him.

Personnel decisions didn’t make DeGuglielmo’s job any easier. The team jettisoned Logan Mankins before the start of the 2014 season and started the staggeringly overmatched Jordan Devey in Mankins’ place for the first few games. Even I could tell Devey was awful. The team started 2-2 and the lack of protection was getting Brady pummeled. But the line situation settled as Stork went into the lineup (as a rookie) and veterans Dan Connolly and Ryan Wendell became staples at the guard spots.

But 2015 resulted in another shakeup as Connolly retired, Wendell fell ill and was placed on injured reserve and Stork spent the early part of the season on IR. DeGuglielmo has to be saluted for work done in getting the rookies mentioned earlier ready to play.

But when injuries struck the offense both on the line and at the skill positions in mid-November, the Patriots offense went into a deep funk and the team lost five of its final eight games.

We can have a chicken-or-the-egg debate about why. Did the Patriots fail to run the ball effectively because they lost first Dion Lewis and then LeGarrette Blount and were left with pedestrian replacements like Brandon Bolden, James White and Steven Jackson? Or was the offensive line unable to execute effectively enough to allow them to.

Did the passing game suffer because Brady had less time to throw when Julian Edelman, Rob Gronkowski and Danny Amendola fell into disrepair, or did the team not have complementary players at wideout and tight end who were good enough to uncover and be factors when those guys were out or diminished?

There’s no doubt Bill Belichick, Josh McDaniels and Nick Caserio are trying to answer the same questions. Because the one thing in this that is inarguable is that, when the poop hit the fan with injuries, the Patriots didn’t have the personnel to carry out the offense effectively nor the ability to morph into something else.

Looking back, the Patriots knew they were screwed up front.

Which is why we saw them slamming their heads against the wall in Miami in Week 17 trying to establish a running game that wasn’t there. Which is why Belichick was taking knees before halftime, kicking off in overtime and actually articulating a lack of aggressiveness offensively being related to worry about strip-sacks.

Sunday was just the culmination of it. The woes of the offensive line were brought onto center stage. The miscommunications. The mental errors (Cannon false start and nonsensical Stork personal foul penalty). The lack of anything resembling cohesion.

DeGuglielmo is the guy that takes the fall, but the issues we saw on Sunday were not related to him alone. And I’d put money down that Belichick will eventually say that as well.