unCovering the Birds: What led to the Nick Sirianni-Zach Ertz altercation? Plus, was the Eagles’ loss to the Commanders cause for concern?

The Eagles’ sloppy and, at times, weird loss to the Commanders got weirder when Nick Sirianni and Zach Ertz got into an altercation during the postgame handshake.

Neither the Eagles coach nor the Washington tight end wanted to get into what happened afterward in Landover, Md., on Sunday, but their brief dust-up saw Ertz take exception to a comment Sirianni made about his performance in the game, sources familiar with the incident told The Inquirer.

The two had to be separated by Eagles chief security officer Dom DiSandro, who then ushered Sirianni into the tunnel at Northwest Stadium.

“Both of us said ‘congrats’ to each other,” Sirianni told reporters after the game.

“We just exchanged holiday pleasantries and kept it moving,” Ertz told The Inquirer not long after.

Not quite.

For more on the incident, listen to the latest “unCovering the Birds” and tune in at the 15-minute mark.

» READ MORE: unCovering the Birds Week 16 vs. Commanders: Sorting through the slop

Sirianni’s frustration with his team’s first defeat in 11 games clearly played a role in his interaction with Ertz, who returned to play in the game after suffering a concussion the previous week. But it was also typical for the 43-year-old coach who has been criticized various times for his sideline and postgame behavior.

Sirianni had dialed down on his outward actions during the Eagles’ winning streak. His players had seemingly followed his lead and often played with discipline over that span. But the Eagles lost their cool vs. the Commanders.

They committed 10 penalties, four of which were personal fouls, with one leading to the ejection of safety C.J. Gardner-Johnson. And there were other mistakes — dropped passes, missed tackles, and blown assignments — that contributed to the loss.

» READ MORE: Nick Sirianni must control Jalen Carter and C.J. Gardner-Johnson

But was Sunday more a byproduct of the Eagles losing quarterback Jalen Hurts early to a concussion or cause for concern considering how they unraveled in the second half? “unCovering the Birds” attempts to answer that question ahead of a rematch with the Cowboys and the NFC East title still on the line.

The latest episode of the podcast also takes a closer look at left tackle Jordan Mailata’s impressive seventh season and whether the former Australian rugby player will finally earn a spot on the Pro Bowl.

It would seem unlikely that voters will keep Mailata out, but stranger things have happened — like the Sirianni-Ertz altercation.

The coach would later call his former player and apologize over a Zoom conference call, sources said. The ex-Eagles tight end played for Sirianni in the coach’s first year in Philadelphia. A Super Bowl champion, Ertz was traded midseason to the Cardinals.

Publicly, Ertz and Sirianni were complimentary of each other after their short stint together. The former, upon his first game back at Lincoln Financial Field last month, received a standing ovation from Eagles fans when the team flashed his image on the screen during the coin toss.

But Ertz could have extra motivation to beat his former team — and his former coach — if the Eagles are to face Washington in the first round of the playoffs. That is the likely matchup based on current projections.