Not every major deadline deal is guaranteed to be a smashing success for contending teams. One week out from the trade freeze, here are five headline-making swaps that flopped.

As we enter into the final week before the trade deadline, we prepare to see several big names on the move. The Ottawa Senators have a trio that seem primed to land elsewhere — Mark Stone, Matt Duchene and Ryan Dzingel — while other top talents include the Philadelphia Flyers’ Wayne Simmonds, New York Rangers’ Kevin Hayes and, if the Blue Jackets can get a deal worth biting on, Columbus’ sharpshooting star Artemi Panarin.

For the teams that land these high-priced assets, it will be seen as an immediate victory, a win that pushes them one step closer to capturing the Stanley Cup. The reality, however, is that not all trades, not even those that include landing one of the most sought after stars, guarantee results. In fact, in several cases in recent history, we’ve seen such deals for the perceived top deadline targets fall absolutely flat in the aftermath of the swap.

Need examples? We’ve got them. Here are five recent deadline deals that fell flat for contending teams:

Vegas Golden Knights acquire: Tomas Tatar

Detroit Red Wings acquire: 2018 first-round pick, 2019 second-round pick, 2021 third-round pick

Tatar had been a consistent 20-goal, 45-point player throughout his five full seasons with the Red Wings heading into last season’s deadline and seemed to be on his way to flirting with those marks again when the Golden Knights swooped in to land the slick top-six winger. He had all the makings of a perfect fit for the surprisingly effective Vegas attack.

But something about the Golden Knights’ system didn’t work for Tatar. Not long after his arrival, he found himself manning the bottom six, and his offense simply didn’t make the move with him from Detroit. Tatar scored four goals and six points in 20 games to close out the campaign before being made a healthy scratch often during the playoffs. He scored just one goal and two points in eight games during the post-season.

Tatar’s tenure in Vegas ended almost as soon as it started, too. Come the off-season, he was flipped to the Canadiens as part of the Max Pacioretty trade. Tatar’s come to life in Montreal, too, scoring 18 goals and 43 points in 58 games this season. If he had displayed that kind of production in Vegas, he might still be a Golden Knight.

Pittsburgh Penguins acquire: Derick Brassard, Vincent Dunn, Tobias Lindberg, 2018 third-round pick

Vegas Golden Knights acquire: Ryan Reaves, 2018 fourth-round pick

Ottawa Senators acquire: Ian Cole, Filip Gustavsson, 2018 first-round pick, 2019 third-round pick

This was supposed to be a home run for the Penguins. As part of a three-way deal that included Vegas and Ottawa, Pittsburgh brought aboard one of last deadline’s prized possessions, center Derick Brassard, and it had seemingly every ounce of potential to put the Penguins over the top. Already rolling Sidney Crosby and Evgeni Malkin on lines one and two, Brassard was set to slot in as a super third-line center, one with second-line talent used in a role that could see him win the matchup game with ease on a nightly basis.

That’s not quite how things turned out.

Across the regular season and playoffs in 2017-18, Brassard managed four goals and 12 points in 26 games — only one goal and four points in the post-season — and wasn’t nearly as impactful as Pittsburgh had hoped. And when he struggled to find his form or his fit this season, the Penguins chose to cut their losses. He was shipped to the Florida Panthers earlier this month and could be dealt a second time before the deadline strikes.

Minnesota Wild acquire: Martin Hanzal, Ryan White, 2017 fourth-round pick

Arizona Coyotes acquire: Grayson Downing, 2017 first-round pick, 2018 second-round pick, 2019 conditional fourth-round pick

There was an arms race emerging in the Central Division, not to mention the entire Western Conference, and the Wild wanted to get out ahead of their counterparts by paying big to land Hanzal, who some considered among the two or three top prizes at the deadline. A big, productive, two-way pivot, he seemed a good get for Minnesota, even if they did have to pay — or vastly overpay, depending on who you asked at the time — to get him. But boy, did it ever backfire. Instead of manning the second line, Hanzal fell onto the third. He managed four goals and 13 points in 20 regular season games and then just a single goal in five playoff outings. The Wild were booted from the post-season in five games at the hands of the St. Louis Blues.

As for the return, Arizona was able to use the first-round pick to nab prospect Pierre-Olivier Joseph, second-round pick to land Kevin Bahl and they still have one more draft choice of which to make use.

New York Rangers acquire: Eric Staal

Carolina Hurricanes acquire: Aleksi Saarela, 2016 second-round pick, 2017 second-round pick

Staal’s move from Carolina was no small deal, and the Rangers’ hope upon acquiring the veteran center from the Hurricanes was that he would bring immediate impact to their top six. That wasn’t the case, though. Staal had difficulties slotting onto either of New York’s top lines, and the results simply weren’t there. Brought in to produce, Staal mustered just three goals and six points in 20 games during the regular season and didn’t register a single point in the opening round of the playoffs as the Blueshirts were ousted in five games by the Pittsburgh Penguins. Staal’s stay in New York ended after his 25-game tenure.

Saarela isn’t yet a contributing member of the big club in Carolina, but he’s putting up solid numbers in the AHL. As for the pair of second-round picks, the Hurricanes used the 2016 selection to nab Teuvo Teravainen from the Chicago Blackhawks while the 2017 second-round selection became project prospect Luke Martin.

Chicago Blackhawks acquire: Dale Weise, Tomas Fleischmann

Montreal Canadiens acquire: Philip Danault, 2018 second-round pick

The Blackhawks went all-in often during their run at the top of the NHL, but a couple of Chicago’s worst misfires came at the 2015-16 deadline. On consecutive days, the Blackhawks made two splashes. The first was for Andrew Ladd, with Chicago sending a pair of picks and prospect Marko Dano the other way. The second — and the one that’s incredibly regrettable in hindsight — was the exchange with the Canadiens to nab Weise and Fleischmann.

Weise was red hot at the time of his acquisition, in the midst of the best campaign of his career, but his production went into the tubes once he arrived in Chicago. Across 15 games, he mustered one assist before scoring a single goal in four playoff outings. His average ice time was less than 10 minutes per game. Meanwhile, Fleischmann scored four goal and five points across 23 total games.

What makes matters worse is Danault has turned into a legitimate top-six center with the Canadiens, and he’s currently on pace for a 15-goal, 55-point campaign.