It's simple enough to detect when Mike Sullivan's seething into a postgame press conference, and not just by the steam emitting from his ears as he steps to the podium.

It's when he repeats a reporter's question back. Out loud. Peering from the corner of his eye.

"Slow start?" came the first response to the first question following the Penguins' flat-liner of a 4-1 loss to the Bruins this evening at PPG Paints Arena. “It was a slow game. Period. We had one guy that … I thought our goaltender was terrific. The rest of it, it’s hard to find a positive.”

That's because there were next to none.

Tristan Jarry was ... not just terrific, I'd thought, but tremendous. He'd be tagged for three goals on 30 shots, but that doesn't come close to accounting for how his teammates left him out for target practice at the rifle range.

No exaggeration, either:

Watch only Kris Letang on that one. Conceding the blue line by nearly 20 feet. Barely breathing on Elias Lindholm in the corner. Showing zero urgency to recover back toward the crease in giving up a goal with 1.4 seconds left.

I don't care that there's one game left in the season. That's not OK.

Neither's this:

Watch only Letang on this one, too. Every white sweater's got at least one black sweater marking as the Bruins enter the zone. Yeah, it might've helped if Ryan Shea hadn't dropped his stick. And yeah, Bryan Rust could've kept closer with Pavel Zacha, who makes the final pass to Fabian Lysell, who couldn't have dreamed he'd someday score his first NHL goal without anyone in his area code. But Letang's covering ... nobody. He just glides to his left, locks up and ... yeah.

Not OK.

My mind's mush after this:

Watch only Letang, yet again. Vasily Ponomarev, a smart kid, does well at center red to stunt not one but two Boston players, leaving the defense with what should be a routine two-on-two. Except that drifts so far off Morgan Geekie that Geekie gets off a shot with such ridiculous force that's in and out of the net before even he realizes it was a goal.

That's just ... disrespectful. To the game. To Jarry to allow him to face a shot like that.

They don't seem to think they can say it, so I will: That's not OK.

Look, I've admired Letang like few others. I've lauded his courage on and off the ice. I was calling him the greatest defenseman in franchise history well before that became common. But he's now 37 years old and, for the first time in his career, he looks like it. He can't utilize that trademark skating and stamina to recover, as he could for the better part of a couple decades. And far worse, he's performing, as he would for the remainder of this game in peculiarly chasing around the Bruins for hits or bad penalties for slashing and boarding, as if ... I don't know, he's just not all there. 

He was out of the locker room before it opened to media, so I didn't have a chance to ask.

But here's what I know: That's not OK.

Not in Game 1. Not in Game 81 of a lost season. Not in several other similar showings of late.

Here's what else I know: This defense corps, as a collective, can't be brought back intact for the 2025-26 NHL season. Not if Kyle Dubas is serious about the Penguins progressing into the next phase of their build, if not necessarily contending. Because, just as it did on this day and as it's done way too often all through the winter, bad/unmotivated defense will undo all else.

What to do?

Well, that's for Dubas to figure out, and it's a tall task: Letang, in addition to obviously being part of a treasured legacy for the franchise, has three more years on his contract at an annual rate of $6.1 million, and he'll be 41 by the time it's done. Erik Karlsson has two more years at an annual rate of a team-high $10 million, and he'll be 37 by the time it's done. Ryan Graves has four more years at an annual rate of $4.5 million, and he'll be 34 by the time it's done.

This group ain't about to get better with age, my friends.

And the rest, to be blunt, is a whole lot of Matt Grzelcyk, with only Owen Pickering and Harrison Brunicke on a clear path up from Wilkes-Barre.

Dubas could use all 1,893,422 of the draft picks he's accumulated toward the next three classes on defensemen, and this storyline wouldn't change. Not for the foreseeable future, anyway. He'll need to make trades. He'll need to add through free agency. And he'll need to do both of those, of course, while creating cap space.

Which means ... uh-huh. Somehow.

The rest of this isn't perfect, and I'm not pretending otherwise. More centers depth's needed. More solidity with the bottom-six up front. And still above all, much, much, much more certainty in goal.

I love what's happened with Jarry. It's been, for me, one of the season's most uplifting developments, right behind Rickard Rakell's career year. Since returning from his second AHL exile and stoning everything in sight March 9 in St. Paul, Minn., Jarry's put up a 2.81 goals-against average, a .904 save percentage and, within the latter, an outstanding .844 save percentage on high-danger shots.

What's more, in the intangible sense, his panic threshold's better than I can recall ...

... in addition to his having palpably matured through all that's occurred these past six months.

“I think he’s grown a lot," Sullivan would say after this of Jarry. "I give him a lot of credit. He’s been through a lot as an individual. He’s done a terrific job just staying with it. And I think, since he’s come back, he looks different in goal. He’s the goaltender that’s played here for quite some time now and has played real good hockey. I think he’s played solid for us. He’s making timely saves time and time again for us.”

He is. And he knows it. And appreciates it.

“Obviously, this season was tough for me," Jarry would say. "It didn’t go the way that I wanted, so I think just going right until the end, that’s my motivation, what I’m playing for. It’s every time you get to put the Penguins jersey on, it’s a privilege, and I expect nothing else from everyone else in this room."

Asked how he fared in this one, he replied, "I thought it was all right."

He knew better. Trust me.

That's encouraging. Just as it's encouraging that youngsters Sergei Murashov and Joel Blomqvist will be along, maybe with a bona fide push, by next season.

But one of the boundless side benefits to Jarry's resurrection over the past month is that it's now more evident than ever the degree to which this defense needs to be blown to bits. Because even as the team's gone 9-5-2 in that span, even as the goals have continued coming, the defense still coughs up far too many breakaways and odd-man breaks, far too much of what Sullivan calls "easy offense." In this game, for instance, of Boston's 61 total shot attempts, an absurd 17 came from high-danger distance.

I asked Sullivan to describe the biggest difference in the Penguins' defending from those catastrophic first seven weeks, when they had an NHL-worst 3.89 team goals-against average through Nov. 23, to the 3.31 mark since then.

“I think it was a collective effort.," he'd reply, still visibly steaming. "I think it boils down to a conscious choice that you make if you’re committed to play defense. And then it’s about details. When we were at our best and we’re capable, I think it was a collective effort and a commitment to play the game the right way. And I think that’s a conscious choice. That’s an attitude, and that’s a decision that players make. But it’s hard to play the right way. You’ve gotta stop on pucks. You’ve gotta win puck battles. There’s an element of physicality associated with defensive play, and I’m not just talking about body checks. I mean getting into people and separating people from the puck, boxing out at the net front and having a certain grit to your game. There’s an honesty to that. And I think that’s a conscious choice that each individual player makes on how much honesty they want to bring to the game.”

I'll reiterate that he can't say who he means if, in fact, he'd prefer to single anyone out. Letang's 100% Core to the core and always will be.

But I'd posit that's part of the problem, too. And changing that also can be a conscious choice.