As a 35-year-old defenseman, John-Michael Liles has experienced a lot in his 800-game NHL career. But until Feb. 29, Liles had never gone through being moved at the trade deadline. Little he had seen before helped him prepare for such a system shock.

Liles had to help wife Erin and 9-month-old daughter Ava move from North Carolina to Boston. At the rink, Liles had to adjust from the Hurricanes’ man-to-man coverage to the Bruins’ zone defense. For Liles, who was used to closing on opponents, letting the play come to him required deep thinking to process what came naturally to his practiced teammates.

“It’s a whirlwind,’’ the short-term Bruin said of shifting from one organization to another with a little more than a month left in the regular season. “You’re going from one system to something completely different. You’re going from one team you’ve played with for several years and players you played with several years to players you’re trying to learn on the fly and systems you’re trying to learn on the fly. You’re trying to get your reads and things like that. It’s not an easy experience. But it almost refocuses you because you’re learning so much at once and learning so many new players.’’

Acquiring Liles and Lee Stempniak made sense for the Bruins. Liles brought an experienced, puck-moving presence to the back end. Stempniak projected to be the three-zone No. 1 right wing needed to play next to Brad Marchand and Patrice Bergeron.

More than two months after his team’s ouster, general manager Don Sweeney still believes the pieces he ceded (2016 third-rounder, 2016 fourth-rounder, 2017 second-rounder, 2017 fifth-rounder, and Anthony Camara) for Liles’s and Stempniak’s short-term services were worthy investments to supplement the Bruins’ would-be postseason push.

“I felt, in the position we were in and the core players having the type of year they were having,’’ Sweeney said, “it was incumbent on the organization to support their efforts.’’

In theory, the additions should have helped. In practice, they did not.

Liles scored zero goals and six assists in 17 games. Stempniak scored three goals and seven assists in 19 games. The Bruins were scoring 3.1 goals and allowing 2.78 per game when they landed Liles and Stempniak. In the 19 games following the trades, the Bruins scored 2.37 and gave up 2.89 per game. The Bruins dropped three spots from their Feb. 29 sixth-place standing to finish one position outside of the playoffs. For Liles and Stempniak, one-quarter of a season was too compressed of a segment to yield maximum integration.

The Bruins did not fail to make the postseason because they acquired Liles and Stempniak. Neither player was at fault for the Bruins’ reduced goals-for rate or their bloated goals-against number following the deadline. Collectively, the Bruins hit the skids at the wrong time.

But the Bruins’ dive after Feb. 29 underscores how deadline trades for players on expiring contracts can be regrettable investments when they don’t produce noticeable results — which is regularly the case. The Bruins hit on deadline deals for unrestricted free agents-to-be such as Tomas Kaberle, Dennis Seidenberg, and Mark Recchi. But they also missed with Jaromir Jagr, Andrej Meszaros, Wade Redden, Greg Zanon, Brian Rolston, Mike Mottau, and Steve Montador.

Of the 11 teams that dipped into the 2015-16 rental market, only three improved both their goals-for and goals-against regular-season rates: Anaheim (Jamie McGinn), Dallas (Kris Russell), and Minnesota (David Jones). Boston and Colorado (Mikkel Boedkker, Shawn Matthias) didn’t make the postseason.

Of the four remaining playoff teams, only San Jose executed pre-deadline trades for unrestricted free agents-to-be: James Reimer, Roman Polak, and Nick Spaling. To obtain those players, GM Doug Wilson parted with Alex Stalock, Ben Smith, Raffi Torres, a 2017 second-rounder, and 2018 second- and fourth-round picks.

Three of the four teams executed more impactful deals last summer. San Jose traded for Martin Jones from the Bruins on June 30. One day later, Pittsburgh landed Phil Kessel from Toronto. St. Louis obtained Troy Brouwer from Washington on July 2. Jones, Kessel, and Brouwer had all of 2015-16 to fall in line with their new teams.

Some rentals pay off. In 2014-15, Chicago GM Stan Bowman traded for Antoine Vermette and Kimmo Timonen. After the deals, the Blackhawks’ scoring improved from 2.9 to 3.42 goals per game. They grew stingier, going down to 2.05 goals allowed per game from 2.38. The Blackhawks won the Cup, which made the assets they gave to Arizona and Philadelphia (Klas Dahlbeck, first- and second-rounders in 2015, 2016 fourth-rounder) well worth the price.

A year later, Bowman tried to do it again. He acquired Andrew Ladd, Tomas Fleischmann, and Dale Weise. While Chicago’s scoring rate increased from 2.81 to 3.05 goals per game, the Blackhawks’ post-acquisitions goals-against rate climbed from 2.4 to 3.05. Ladd (1-1—2 in the playoffs), Fleischmann (0-0—0), and Weise (1-0—1) could not help their new team beat St. Louis in the first round. The Blackhawks traded Marko Dano, Philip Danault, their 2016 first-rounder, and 2018 second- and third-round picks for the three UFAs-to-be, none of whom the Blackhawks will re-sign.

Ladd was the only 2015-16 deadline deal that involved a first-round pick. In that way, teams are wising up. The year before, Los Angeles (Andrej Sekera) and Nashville (Cody Franson, Mike Santorelli) traded first-rounders. In 2013-14, St. Louis’s disastrous acquisition of Ryan Miller in a package from Buffalo included two first-rounders going the other way.

The mistakes are involving less pain for the teams acquiring the rentals. But it’s still pain that could be avoided altogether. It’s an inefficient and expensive exercise to trade for temporary reinforcements.

On future deadline days, teams will continue to gather in their war rooms and work the phones, simply because it’s the way the league has always operated. The smart ones will conclude it’s a tradition that’s better ignored.

NUMBERS GAME

Panthers to use analytics more

Dale Tallon accomplished good things during his six seasons as Florida GM. On Tallon’s watch, the Panthers built for the future by drafting Aaron Ekblad (No. 1, 2014), Aleksander Barkov (No. 2, 2013), and Jonathan Huberdeau (No. 3, 2011). The top-three trio, along with fellow draftees Nick Bjugstad and Vincent Trocheck, give the Panthers good foundation pieces for years to come. Of the five, Bjugstad is the oldest. The center will not turn 24 until July 17.

But Tallon, officially booted upstairs to president of hockey operations last Monday, didn’t exactly have to execute hard decisions to draft his three cornerstone players. They were slam-dunk picks.

Meanwhile, Tallon’s six-year stewardship includes old-school transactions the small-market Panthers found difficult to absorb. Tallon, the former Chicago GM, signed ex-Blackhawk Dave Bolland to a five-year, $27.5 million whopper that doesn’t expire until 2019. Bolland scored one goal and four assists in 25 games in 2015-16. Tallon traded four picks for Jiri Hudler, Teddy Purcell, and Jakub Kindl.

Teams with deeper pockets can afford to make such mistakes. The Panthers cannot.

Under their new management structure, Lynn native Tom Rowe replaces Tallon as GM. Eric Joyce and Steve Werier were promoted to assistant GMs. While Rowe is a hockey lifer, neither Joyce nor Werier have traditional NHL backgrounds. Joyce has a graduate degree from Harvard’s Kennedy School of Government. Werier practiced law.

The Panthers plan to dive deeper into statistics to complement in-person viewings and video analysis. In that way, they’re hoping to develop richer personnel reports to target players that other organizations might have overlooked.

“I really think it’s an important component,’’ Rowe said during a conference call. “It’s not the only component. Eric Joyce comes into play. He’s a real bright guy on the analytics side of things. But it’s only one component we’re using. It’s supplemental information that we think is important. Dale believes in it. I believe in it. When you’re making decisions in the National Hockey League today, you’re talking about an awful lot of money. It helps you limit your mistakes.’’

ETC.

Capitals don’t get emotional

A trigger-happy executive would not take another second-round exit as stoically as Brian MacLellan. The Washington GM took a matter-of-fact approach about his team’s loss to Pittsburgh, continuing the Capitals’ tradition of earlier-than-expected postseason departures.

“I like the team we have now,’’ Mac­Lellan told Washington reporters last Monday. “I think it’s a good team. With me, I’m as frustrated and agitated as the players and coaches that we didn’t accomplish more. But I think there’s 5-6 teams that should compete for the Cup. We’re one of them.’’

MacLellan, who was named a finalist for the NHL’s General Manager of the Year Award last Wednesday, is deserving of his nomination. Some other GMs would not be so accepting of a second-round loss. They’d make reactionary moves instead of taking a deep breath and examining their rosters logically instead of emotionally.

When coupled with recency bias, the random nature of the playoffs can prompt ill-advised mistakes. Behemoths like Washington can lose. Where other rookie goalies have quivered in the playoffs, iceman Matt Murray bricked up his net. Pittsburgh’s third line of Carl Hagelin, Nick Bonino, and Phil Kessel played well. The Penguins shrugged off Kris Letang’s one-game suspension. Funny things happen in small sample sizes, even to regular-season titans like the Capitals.

Nothing should change for the Capitals next season. In fact, they could even get better. Jason Chimera, Mike Richards, and Mike Weber, all depth players, are their only UFAs-to-be. Lead dogs Alex Ovechkin, Nicklas Backstrom, Evgeny Kuznetsov, and Braden Holtby are under contract and in the sweet spots of their careers.

The stickiest situation MacLellan will face is re-signing Marcus Johansson, who will be restricted. The versatile Johansson is an important player. He can be the No. 3 center behind Backstrom and Kuznetsov. He can play both wings. Johansson, who earned $3.75 million in 2015-16, will be considering Nazem Kadri’s six-year, $27 million payday as a comparable. The Capitals can afford to give Johansson the raise he deserves.

With Johansson under contract and improvement expected from Kuznetsov, Andre Burakovsky, Dmitry Orlov, and Tom Wilson, the Capitals should be in even better shape to contend for the Cup in 2016-17.

But MacLellan is also realistic enough to identify next season as the last year for this group. T.J. Oshie, Justin Williams, and Karl Alzner will be unrestricted after 2016-17. Kuznetsov and Burakovsky will be restricted. Kuznetsov is developing at a pace where he will command a salary north of $7 million annually on his next deal. At that price, MacLellan will not have enough free cash to bring back other core pieces.

“I don’t know that the window closes off,’’ MacLellan said. “But it’s got to change. Money needs to be allocated to different players. Sometimes that squeezes out other players. The situation will change after next year.’’

Versatility sparks Sharks’ PP

Through 15 playoff games, San Jose’s power play was humming at 28.8 percent, best of the conference finalists. It helps to stack a first unit with massive talent: Brent Burns, Joe Thornton, Joe Pavelski, Patrick Marleau, and Logan Couture. But what makes the Sharks’ group so dangerous is its versatility. Some teams have defined roles for their man-up players. The Bruins deployed Torey Krug at the point, David Krejci as the left-side high guy, Patrice Bergeron as the bumper, Ryan Spooner on the right-side half-boards, and Loui Eriksson as the net-front/goal-line presence. For the most part, they stayed there. In comparison, the Sharks are all over the place. Burns regularly drifts down the wall and into the low slot. Thornton moves up and down the right side. Pavelski sets up for one-timers at the left circle and goes in front for tips. Opponents can’t predict where the Sharks are going. It makes killing penalties against the Sharks insanely hard.

Return not guaranteed for Zboril

Under normal circumstances, 19-year-old Bruins prospect Jakub Zboril would return to St. John this fall after some repetitions at training camp. But there were enough red flags in Zboril’s performance in 2015-16 that going back to his QMJHL team is not a guarantee. Zboril scored only six goals and 14 assists in 50 games last year. It was an alarming dropoff from Zboril’s 13-20—33 line in 44 games in 2014-15, production that prompted the Bruins to select the defenseman 13th overall. Zboril has one season of Czech Republic eligibility, which is a factor in determining his 2016-17 destination. “It’s far-fetched,’’ GM Don Sweeney said of assigning Zboril to Providence. “There’s a series of steps that has to be taken before that’s considered and all other situations are satisfied.’’

Linemates complementing Drouin

The skilled Jonathan Drouin has been one of the Lightning’s more dangerous offensive players in the playoffs. Through 13 games, the right wing was the team’s third-leading scorer with 11 points, three behind top-liners Tyler Johnson and Nikita Kucherov. Drouin’s speed, hands, and creativity were always good enough to create offense. But Tampa Bay coach Jon Cooper made the right move by deploying Drouin with Valtteri Filppula or Ondrej Palat as linemates. Drouin operates so rapidly that it’s hard for linemates to follow his pace. It has led to disjointed attacks in the past. But Filppula and Palat are two of Tampa’s smartest players. Even though Palat can’t match Drouin’s speed, he processes the game well enough to read off the talented right wing and anticipate what he’s going to do.

Loose pucks

Jonathan Marchessault is only 25. But he will become unrestricted on July 1 as a Group 6 free agent because he’s played in fewer than 80 games. The Lightning would like to keep the shifty forward, but they have to re-sign RFAs Nikita Kucherov, Alex Killorn, and Vladislav Namestnikov. Marchessault will draw interest on the open market . . . Zach Werenski, the No. 8 overall pick in 2015, has been excellent for Lake Erie, Columbus’s AHL team. After being a point-per-game player as a freshman at Michigan, Werenski has had no trouble transitioning to pro hockey. Werenski had four goals and six assists after nine games through two playoff rounds. Werenski, Seth Jones, and Ryan Murray are three foundational blue-liners for the Blue Jackets . . . It’s hard to imagine any playoff moment being better than Phil Kessel misunderstanding Pierre McGuire’s query about his conditioning. “It’s not good, eh?’’ Kessel answered when the NBC commentator asked him about his breath after Game 3 against the Lightning. Kessel laughed it off after he understood the question. Dressing rooms being what they are, however, I would be disappointed if Kessel’s teammates don’t regularly fill his stall with Altoids.

Fluto Shinzawa can be reached at fshinzawa@globe.com. Follow him on Twitter @GlobeFluto. Material from interviews, wire services, other beat writers, and league and team sources was used in this report.