Just when it looks as if the Flyers might have finally solved the season-long riddle of their penalty kill, their once potent power play has gone into hiding.

Once among the top six, it had slipped to 17th in the NHL prior to Friday night's games. During their current five-game swoon, the Flyers are 2 for 24 on the power play, going 1 for 5 in Thursday's 3-2 loss to the Bruins. Dating back to a 5-4 shootout loss to New Jersey on Feb. 13, they have scored five power-play goals in 39 tries, a 13 percent clip that would place them dead last in the league, behind Edmonton's current 14.2 percent clip.

For a team that has spent the bulk of its season starved for secondary scoring, this is particularly toxic. And yet it wasn't — at least right away.

The Flyers won six in a row after that New Jersey game, and it wasn't difficult to figure out how. They stayed out of the box, allowing momentum to build from uninterrupted line changes. The Flyers' calling card this season has been five-on-five play and faceoffs. They've been terrific in both. Staying out of the box, and sending the other guys to it, do not become as integral to success.

But the power play is a concern, for both its results and as a reflection of the overall malaise that has seeped into the Flyers' game. "It's all about how we're moving the puck on the power play,'' Jake Voracek said before the recent back-to-back games. "If we're moving our feet,  moving quick, if we're making hard passes, we're really hard to stop.''

That can apply, really, to the overall tone of their downturn. Claude Giroux used an expletive to describe that power play against Pittsburgh, before it showed signs of life against the Bruins on Thursday. But it's not as if their feet stop working only when they're a man up. It's five-on-five too, which is the main reason the penalties they avoided so impressively in February have returned like a March nor'easter. This isn't just about running into referees who like to call penalties. If so, Brian Gionta would never have been able to score that late first-period goal Thursday that negated so much good work in that period by the Flyers. Tommy Wingels' trip of Wayne Simmonds was open-ice blatant — and consequential, allowing Zdeno Chara to thread a pass up to Gionta, who had slipped past Radko Gudas after Brandon Manning was caught joining the sabotaged rush inside the Bruins zone.

Flyers forward Claude Giroux.
PAUL VERNON / AP
Flyers forward Claude Giroux.

No, the Flyers are indeed falling into the same (mental) fatigue-driven bad habits that bit them in late November. Slashes, hooks, sticks to the head – they're the easiest to see and thus to call. "It's not effort-related,'' said Sean Couturier, whose own fatigue has manifested itself in a goal drought. "Guys are battling hard. I don't think it's physical. I think it's maybe more mental. It's just details, especially this time of the year. And down the stretch those are probably going to make a difference in the long run. We've got to come back to being focused and paying attention to those small details. We've got to show we're stronger than that.''

"I'm pretty confident we will bounce back. We'll fix some things, clean up some things. I think we'll be all right.''

If you're looking to support that contention, well, the much-maligned penalty kill is your silver lining. Over the last 14 games, opponents have scored just four goals in 26 power-play opportunities against the Flyers. That 84.6 percent clip would place them just below San Jose at the top of the league's penalty kill.

"I think we've been playing better of late,'' said Val Filppula, who assisted on Jori Lehtera's shorthanded goal Thursday, and whose chemistry with him has been a key element of  the improved effort. "Obviously, going forward you need to have a good penalty kill, and we're moving in the right direction.''

That was the overall theme  Thursday and again after practice Friday, when Flyers coach Dave Hakstol said, "We won the specialty teams battle. On the road, that's a good place to start. That should give you a good chance to win the game.''

One more power-play goal would have done it. But the Flyers did close to nothing when Brad Marchand went off the ice for slashing with 6 minutes, 39 seconds left in the game, and the Bruins super-pest stabbed them for it with 22 seconds left. Now come visits from Winnipeg on Saturday and Vegas on Monday – two more chances for the Flyers to put all the pieces together before the Ides of March.

"It's close,'' Filppula said. "We have a young team. And once we get one, I think we'll be all right.''