Bruins have a killer assistant coach in Sacco

They come crashing over the boards in waves. One after another, they flood their zones and fluidly follow the puck, patiently waiting to attack the possessor or prod him into a poor pass or decision.

Say hello to the Bruins’ penalty killers, or as opponents might call them, the buzz killers.

The Bruins have been among the NHL leaders in erasing power plays all season, killing at an 85.5 percent rate heading into the weekend.

The reasons for the success are multifold, including outstanding goalie play (always a team’s best penalty killers), depth at forward (they’ll run up to seven skaters out), and a stable of horses on defense.

The person most responsible for the boon while shorthanded doesn’t wear a game-day sweater.

Say hello to Joe Sacco.

An assistant on the Bruins’ coaching staff since the Claude Julien days in 2014-15 — and a Bruins fan since his Medford Youth Hockey days — Sacco is the man who designs and develops his club’s attacks and counterattacks while down a skater or more.

Despite a major roster overhaul, Sacco, the former Avalanche head coach, has integrated new killers and maintained the unit’s high level of success.

“He does a great job. It’s plain and simple,” coach Jim Montgomery said earlier this season. “We were No. 1 last year and this year we’re off to a great start again. Obviously, our goaltenders have a great deal to do with that, but I just think his game plan, his execution, and the players, they understand his game plan at a high level. Because we don’t have [Patrice] Bergeron, we don’t have [David] Krejci, we don’t have [Tomas] Nosek, [players] that were a big part of our penalty kill. So, we’ve got new bodies in there and they’re still doing a great job.”

Penalty-killing units are often made up of fourth-liners and/or players not counted on for heavy minutes or high offensive production. The Bruins don’t subscribe to that somewhat dated philosophy. Instead, Sacco rolls out players from every line and defense pairing.

Forwards Brad Marchand, Charlie Coyle, Pavel Zacha, Jake DeBrusk, Danton Heinen, Trent Frederic, and Johnny Beecher rotate on the kill. On the back end, Brandon Carlo, Hampus Lindholm, Charlie McAvoy, and Parker Wotherspoon clear pucks and bodies in front of Linus Ullmark and Jeremy Swayman.

One of the club’s most valued members of Sacco’s squadron, Derek Forbort ,is due back soon after rehabbing a nagging groin injury.

The players’ ability to quickly make clears allows them to get off the ice in a flash. The shorter the shifts, the fresher the legs.

The key to the high-level performance is in the preparation, and that’s where Sacco comes in. His detailed scouting reports on upcoming opponents and how they run their power play is the foundation for the kills.

“The PK basically, for me, it’s just about giving the players the accurate information that they need going into the opponent that we’re playing on that particular night, trying to find their strengths as a group, what they do well on their power play, what are their tendencies and what we can do to try to take that away from them,” said Sacco, a defensive specialist during his 13-year NHL career. “It’s not anything that is new, it’s just you look at a power play and you say, ‘OK, they have a tendency to do this, and this is option one, this is option two. What can we do to take that away or how are we going to take that away from them?’ ”

As important as the pregame plan is, in-game adjustments are a priority. Sacco must be on top of the cat-and-mouse game.

“Good power plays, they adjust, they’ll see [your strategy], and they’ll make adjustments accordingly. And then we just try to make adjustments as well as the game goes on,” said Sacco.

“If there’s something that we need to check to change, whether it’s the forecheck, maybe they’re doing something different on their breakouts and they’re having success against us, we may have to change that up or something in zone or faceoff alignments. That’s very important because you start obviously the PK with a faceoff and your alignment is very important. What are you doing off the draw if you win, what’s the plan? What’s the plan if we lose? Those are things that we always discuss. So, it’s just about trying to give the players the best information possible and having them go out and execute it.”

Sacco’s scouting reports need to account for an abundance of possibilities. Teams don’t always have one cookiecutter approach to the power play. The top unit may have an entirely different strategy than the secondary group. All possibilities must be covered.

“Teams within the course of a game, one unit with the same team might use a delay entry and the second unit might use a speed entry where they’re not delaying. So, our guys have to shift on the fly to that,” said Sacco. “If we see a delayed entry, a lot of times we’ll rotate into a box. Now all of a sudden maybe they hop over the bench and there’s another unit coming out that’s all speed. So, we have to be able to adjust to that. We don’t go into a box for speed.

There’s a lot of things going on that happen quickly, but they know going into the game, what we’re doing if they do this or they do that, which I think helps them, because they just want to know. They just want to know, ‘Hey,

OK, if they do this, what are we doing? If they do this, what are we doing?’ Whether it’s up ice, on faceoffs, or in the D-zone.”

When it comes to building his cadre of killers, Sacco said it’s a combination of identifying and recruiting players who fit his systems, as well as others who volunteer for duty.

“There’s guys that take on certain roles or have been in that position before this year. We have a couple of guys killing this year, a couple of players that are newer to our organization, like Beecher for example,” said Sacco. “I think he killed in Providence last year, but now this is his first time in here, so you’re always trying to implement new players in there and give them an opportunity.”

Sacco’s charges are quick with kudos. “He takes such pride in having the pre-scouts for us and having a great game plan. It’s something we take pride in as a team,” said Swayman. “Our four are going to outwork their five every time, and it’s been a momentum builder for us. Any time we get on the PK, we know it’s going to be a momentum shifter, and that’s scary for teams coming to play us because we know that we’re going to get it done.”

Sometimes, the compliments are backhanded.

“They’re unbelievable. It’s terrible practicing against them. Sometimes you think your [power play] should get better when you practice against the best PK in the league, but our PP is getting worse from that,” David Pastrnak said with a smile.