Maybe the best defense Aaron Glenn put together all week came on Thursday, when he was filled with explanations for why his defense had surrendered at least 37 points for the third time this season.

“Nail-biter, wasn’t it?” the Detroit Lions defensive coordinator said after his players were mauled by the Chargers in Sunday’s 41-38 win. “Yeah, those games are tough, but they’re also exciting.

“And, man, I’m happy we came out with a victory, all right? That was a — and those games happen in this league.”

And as far as being happy about a win? He should be ecstatic — and relieved the offense saved his bacon.

Stuff happens. That was the theme of Glenn’s news conference Thursday. And he’s right. Stuff like this does happen. But it tends to happen to bad teams, not to 7-2 teams in the hunt for the NFC’s No. 1 seed.

Hey, any defense can have a bad day — and Glenn was sure to cite the example of the Ravens losing, 33-31, to the Browns on Sunday — when he was asked if the Chargers’ offensive output was a mere anomaly.

“This is the NFL,” he said. “That’s what that is and it happens. I mean, no one thought Cleveland would put 30-something points on Baltimore, but it did.

“And again, this is not peewee football, fellas. This is the NFL, so things happen and, man you fight your (butt) off every week to make sure it doesn’t and our guys do a damn good job of that.”

But let’s remember this about the Ravens’ defensive stumble. It was their first of the season. They haven’t given up more than 24 points in a game otherwise.

The Lions’ defense? This was the third time in nine games it has allowed at least 37 points. Once every three games isn’t a mirage or an anomaly. It’s a common occurrence, if not an outright trend.

Yes, those defensive struggles have come against good offenses, such as the Chargers and the Ravens, but also against the Seahawks’ mediocre offense.

Glenn also wasn’t beyond leaning on the old, reliable “good quarterback” excuse.

“Yeah, well the first thing that comes to my mind is, I knew this quarterback was good,” he said of L.A.'s Justin Herbert, “but damn, he’s really good.”

Mmm-hmm. He sure is. Big arm. Big stats. One Pro Bowl. No playoff wins. Herbert’s basically Matthew Stafford with a hairband.

To be fair, this isn’t all on Glenn. The defense doesn’t have the same level of talent as the Lions’ offense. And when the trade deadline rolled around, general manager Brad Holmes didn’t make a single move to help, leaving the pass rush and the secondary still lacking, partly because of injuries to starters.

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Losing players such as C.J. Gardner-Johnson, Emmanuel Moseley and James Houston has been cited by some fans and media as key reasons why the defense, while still a top-10 unit, hasn’t been as consistently potent as it could be.

I don’t subscribe to that theory, but I still offered it to Glenn as a possible explanation for the defense’s struggles. He slapped it down. Hard.

“We play football,” he said. “And it’s not like you’re going to go out and get Deion Sanders right now. That’s just what it is.

“Listen, the guys that we have, have put us in a position — we’re a top-10 defense. So listen, I don’t even look into that. I think that’s one of the stupidest things you can think about. So listen, we have great guys, but our guys go out there and play hard, that’s what they’re going to do.”

This is where Glenn is in a bit of a pickle. He can’t publicly criticize the lack of talent and depth, because that’s tantamount to criticizing Holmes. Instead, he has to figure out what to do with Holmes’ precious but unproductive draft picks, such as Levi Onwuzurike and Ifeatu Melifonwu.

At least Holmes kinda tried to make it up to Glenn. Like a spouse who forgets their anniversary by grabbing a quick fistful of garden flowers, Holmes this week signed Bruce Irvin, a 36-year-old defensive end who hasn’t played in 10 months.

On Sunday, when the Lions host the Chicago Bears, they’ll also face one of the players who really could have helped them: Montez Sweat, a defensive end acquired from Washington for a second-round pick. Maybe the price was too steep for Holmes, who probably would have had to surrender his late first-rounder to beat the Bears’ pick likely near the top of Day 2.

But even Dan Campbell noted that Sweat is a good player and believes he already has 10 pressures in two games with the Bears. He also had three quarterback hits in last week's 16-13 win against the Carolina Panthers.

Campbell also spoke this week about the defense’s struggles and offered a sobering review of the poor communication and the failure to be in sync even on some calls, noting “even if it’s the wrong call, it’s right if we’re all on the same page … we need to make a call and live by the call, and not try to live in two worlds.”

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Consider Ben Johnson’s offense, which had the wrong personnel on the field but still audibled into a different play that resulted in David Montgomery’s 75-yard touchdown run.

Is Glenn’s message not getting through? Is he not teaching it right? Or are the players simply not good enough to be consistent against good quarterbacks and good teams — you know, like the ones they’ll face in the playoffs?

“Guys, we’re still a pretty damn good defense,” Glenn said, seemingly speaking to his players. “We’ve played some good defense this year and, man, get that out your head from everything that you’ve seen, every — what you read. Just understand what we’ve done and what we’re doing and focus on that.”

I often don’t know what to think of Glenn. I’m not sure if he speaks with reporters the way he thinks a head coach should, unflinching and self-assured. Regardless of how he comes off, what’s most important is that he needs to be brutally honest with himself about his defense’s shortcomings if he hopes to fix them before the Lions face another "good quarterback" ... in the playoffs.

Contact Carlos Monarrez: cmonarrez@freepress.com. Follow him on Twitter @cmonarrez.

This article originally appeared on Detroit Free Press: Detroit Lions defense sure doesn't look playoff-ready right now