Nick Sirianni scorches Jonathan Gannon and the Eagles defensive staff | Marcus Hayes

League sources said Thursday that, after Sunday’s blowout loss to the Chiefs, Eagles rookie coach Nick Sirianni blistered his defensive coaching staff in meetings early this week.

He targeted rookie coordinator Jonathan Gannon in particular. Sirianni is frustrated at Gannon’s toothless, amorphous scheme; Gannon’s timid calls; and Gannon’s poor utilization of star players like defensive tackle Fletcher Cox and Darius Slay.

“It was some tough conversations in the defensive room this morning,” Sirianni said Monday. This, according to the sources, was an understatement.

Sirianni was mad. But it sounds like Gannon didn’t get the message.

Gannon’s defense hasn’t defended much of anything in three weeks (the 49ers didn’t score much because quarterback Jimmy Garoppolo was awful).

Still, on Tuesday, Gannon insisted Cox is playing fine; but this is demonstrably untrue, partially due to how Gannon uses him. Gannon also said that, for the moment, he won’t put a sixth defensive back on the field, even if a dynamo like Tyreek Hill might go virtually uncovered, which is essentially what happened on the Chiefs’ second touchdown Sunday.

Finally, Gannon revealed that he doesn’t have a scheme, per se.

Obviously.

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He also made clear that doesn’t know what his players do best. Cox is most productive in a 4-3 alignment, not a 3-4. Slay shines in man-to-man coverage, not zone.

Gannon needs a telescope to see his safeties, who routinely lined up so far off the line of scrimmage Sunday that they couldn’t tell whether it was Patrick Mahomes or Andy Reid playing quarterback. The Eagles’ rushing defense allowed 200 yards, which sank them to 31st in the league.

If you were Gannon’s boss, you’d be angry, too.

When Gannon says “I don’t have a scheme,” he sounds ridiculous, but his philosophy makes sense. His execution, to date, does not.

Gannon means that, instead of being a 4-3 defense or a 3-4 defense or a wide-nine disciple, he uses multiple fronts with shifting responsibilities. This strategy keeps the opposition guessing, but at this point, it keeps his own players guessing, too. They play slowly. They’re thinking about their assignments instead of executing them instinctively. They hesitate, and they are lost.

The stars don’t like it.

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Slay said Sunday, “We just have to find what we need to do. I just try to play my hardest, whatever call [Gannon] gives.”

Cox said Wednesday, “It’s hard to get settled into a game when you’re playing so many positions and doing so many things.”

Gannon speaks about putting his players “in the best position possible to succeed.” Fine. For the moment, that position is a predictable, 4-3 defense that blitzes about 25 percent of the time and, when faced with five receivers, uses six defensive backs. And not Eric Wilson.

Gannon, 38, was considered the jewel of Sirianni’s young coaching staff. Gannon spent the past three seasons coaching defensive backs in Indianapolis, where Sirianni served as offensive coordinator. League sources say at least three other teams were prepared to offer Gannon a job as defensive coordinator.

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Maybe they dodged a bullet.

Hill burned linebacker Eric Wilson for a touchdown in the second quarter. Hill, the most explosive receiver in the NFL, should have been covered by a defensive back. That would have meant replacing a linebacker with a sixth DB. Gannon refuses.

“We’re not really a dime team right now,” he said.

Yes. Reid knew that, so he matched Hill against Wilson.

Clearly, Gannon believes that Wilson and Alex Singleton, his linebackers, are better in pass coverage than rookie corner Zech McPhearson and Andre Chachere, a Colts practice-squad player whom Gannon coached last season.

Similar mismatches will happen in the future, including Sunday at Carolina, at least until second-year safety K’Von Wallace returns from injured reserve. Ezekiel Elliott separated Wallace’s shoulder, so Wallace will miss at least one more game, and as many as four more.

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This is the definition of insanity. As The Inquirer noted Tuesday, Wilson and Singleton have been targeted 35 times and allowed 30 completions for 272 yards and four touchdowns.

Gannon said that every defensive call has “soft spots” that require “hard duty” from the players who find themselves mismatched. Even poor offensive coordinators coaching mediocre quarterbacks with pedestrian weapons find those soft spots. You know, like the Panthers.

Especially if they’re given all day to do it.

The Eagles blitz less frequently than any other NFL team, 10.8% of the time, according to pro-football-reference.com. They have pressured the quarterback 23.7% of the time, which is 21st in the league. They have forced two turnovers, third worst in the league.

Bringing extra pressure would do several things.

It would free Cox from some of the double teams that, in his 10th season, he is finding harder to beat. It would let Slay and fellow corners Steven Nelson and Avonte Maddox play tighter and make more plays on the ball. It would quicken the quarterback’s internal clock, so mismatches might be less damaging.

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The Eagles’ play callers offer an intriguing contrast.

Sirianni, who calls the offensive plays, is coaching like a man with nothing to lose; gambling on fourth downs, calling trick plays, taking deep shots with a raw quarterback and rawer receivers.

Gannon, meanwhile, is coaching like a coach who doesn’t want to make a mistake; rushing only three or four players, playing lots of zone with his safeties 20 yards off the line of scrimmage, essentially ceding the run, and asking his pass defenders to just keep receivers in front of them.

Sirianni and Gannon are not cut from the same cloth. The thing is, one of them’s the boss.

And the boss ain’t happy.