On May 23^rd, 2025, the New York Islanders hired Mathieu Darche to be the franchise’s next General Manager, succeeding Lou Lamoriello. 16 days earlier, the Islanders won the 2025 Draft Lottery, giving them the right to select franchise defenseman Matthew Schaefer 1^st overall in Darche’s first draft. The club was well within playoff contention throughout the season and finished with a 43-34-5 record for 91 points. Matthew Schaefer shocked the world, scoring 23 goals and 59 total points (2^nd on the team in scoring behind Mathew Barzal’s 72), en route to what will likely be a Calder Trophy-winning season. Despite failing to qualify for the playoffs, the 2025-2026 season suggests that the New York Islanders are back on track, improving by 9 points and 8 wins in the standings from the 2024-2025 season. This is due in large part to Schaefer’s emergence as one of the league’s premier young defensemen, but also because of the savvy moves Mathieu Darche made in his first year as a GM. This article will discuss those moves in greater detail, compare Schaefer’s rookie season to other outstanding defensemen since the 2007-08 season, and provide an offseason outlook for a team that’s on the precipice of becoming a perennial Eastern Conference contender once again.

Matthew Schaefer’s 2025-2026 season isn’t just worthy of a Calder Trophy, but it’s indicative of a statistical anomaly within the AB Framework when evaluated against meaningful NHL comparables. For more information on how the AB Score is calculated and what it stands for, please refer to this article The Intersection of Data Analytics and Managerial Philosophy in Professional Hockey – hockey free for all.com (HOME OF THE ADVANCED BRACTON).

In the AB Score vs Age distribution graph above, Schaefer’s 2.97 AB Score at age 18 suggests that he’s wildly outside the normal developmental curve for defensemen. As the graph dictates, most 18-20-year-old defensemen hover around replacement level or slightly below, with true quantifiable impact occurring around 22. As the graph details, Schaefer isn’t following that progression; instead, he’s producing years ahead of his peers. He’s obviously also outplaying his 950k rookie contract, as the salary cap section of this article will discuss in greater detail. This luxury provides the Islanders with unique roster-management flexibility, which is greatly needed this offseason, as the latter parts of this research will analyze.

The rookie distribution graph provides an even clearer picture of the rarity of Schaefer’s immediate impact. After filtering out rookie defensemen who played fewer than 40 games in their first season, most players cluster between 0 and 1 AB, with very few exceeding 1.5 AB. Schaefer almost tripled it at 2.97, which puts him not at not only one of the best rookie defensemen of the era, but in the upper echelon of defensemen in all of hockey. When compared to recent Calder-winning defensemen, Schaefer’s 2.97 AB is higher than Cale Makar’s 2.54 (age 21), Moritz Seider’s 2.15 (age 21), Lane Hutson’s 2.91 (age 21), and Aaron Ekblad’s 2.00 (age 18). Outside of Ekblad, Schaefer outproduced his comparables despite being significantly younger, setting a trajectory that puts him amongst the league’s best.

Many in the industry praised Schaefer’s offensive performance this season, as few expected him to double his goal tally from his last two seasons with the Erie Otters during his first professional year. In 2023-24, he scored 3 goals, followed by 7 in 2024-25, and then 23 goals in his debut NHL season. Schaefer was also 2^nd on the Islanders in takeaways, and had an amazing 2-1 penalty drawn-taken ratio. For a defenseman playing almost 25 minutes a night, the mistake-minimization ability, coupled with the 59 points in a full 82-game season, is simply unheard of. Schaefer’s clearly the franchise defenseman the Islanders hoped he’d be; now it’s up to Mathieu Darche and his management staff to surround him with the talent he needs to win, a job they’ve already been doing incredibly well thus far, as the rest of the article illustrates.

Before the roster management and salary cap discussion, one of the most important of Darche’s decisions this year was behind the bench, replacing head Coach Patrick Roy with Peter DeBoer. Prior to the trade deadline, I wrote an article about the Anaheim Ducks and coach Joel Quenneville’s immediate impact on the trajectory of that franchise (read it here Joel Quenneville Has Altered the Trajectory of the Anaheim Ducks — The League Shouldn’t Make the Same Mistake with Peter DeBoer – hockey free for all.com (HOME OF THE ADVANCED BRACTON)). The article argued that, despite being out of the league for a period, Quenneville’s underlying metrics show he’s the best coach in the sport, and the Ducks are benefiting from his hire immediately. Currently, the Ducks have a 3-2 series lead on the back-to-back defending Western Conference Champion Edmonton Oilers, further illustrating the point of that article (despite the AB projecting a slight advantage to Edmonton in my playoff prediction article here (2026 HFFA Stanley Cup Playoff Predictions – hockey free for all.com (HOME OF THE ADVANCED BRACTON)).

However, this relates to the New York Islanders because the model forecasted that other high-profile coaching candidates were available if teams were looking to make a leadership change. The Vegas Golden Knights fired Bruce Cassidy a few weeks after this article was published (read here, John Tortorella Hired in Vegas, Why the Golden Knights Will Regret Firing Bruce Cassidy – hockey free for all.com (HOME OF THE ADVANCED BRACTON)), and, at that time, the model projected that DeBoer was the best available name on the market. The reasoning behind his projection centers on a Coaching AB profile characterized by consistent value creation, historical team efficiency, and a track record of taking multiple franchises to the Stanley Cup Finals. The graphic below presents a comparison between the Islanders’ former coach, Patrick Roy, and Peter DeBoer.

As shown in the graphic, DeBoer surpasses Patrick Roy in all key AB coaching metrics. His 0.767 Coaching AB Score places him among the league’s top coaches, with outstanding figures in Return IMP% (50.4% of players coached by DeBoer improve their AB Scores in back-to-back seasons) and Advantage% (52.8% of players perform better under DeBoer compared to their previous coach). It’s also notable that DeBoer’s average player AB of 1.205 was higher than this year’s replacement-level threshold of 1.17, which is incredible given the volume of players DeBoer has worked with in his career.

Despite the team going 1-3 in their 4 games with Peter DeBoer as Head Coach, the willingness to make a controversial move like this reflects potential elements of Mathieu Darche’s overall approach to team building and general management. He ignored public perceptions and made a decision he felt was best for the long-term future of the New York Islanders. This differed from the Vegas Golden Knights’ decision to fire Stanley Cup Champion Bruce Cassidy and replace him with John Tortorella (who doesn’t have an agreement to coach the Golden Knights beyond the Stanley Cup Playoffs), because Darche committed four more years on top of the remainder of 25-26 to DeBoer. The coaching upgrade becomes a foundational piece for the Islanders’ direction moving forward, and this, combined with the roster moves discussed in the remainder of this article, suggests that Darche and management’s plan is already coming to fruition.

While Matthew Schaefer’s emergence is the clear takeaway from the Islanders’ 2025-26 season in terms of AB, the team-wide AB Score distribution indicates that multiple core players stepped up for the club this year. It reflects a roster that was quietly reshaped by Mathieu Darche to maximize immediate performance and prioritize long-term upside, but it also did not commit to players below replacement level. This lineup balance is critical and is indicative of the moves Darche made in his first offseason.

One of Darche’s most impactful additions was Emil Heineman, who finished the season with 22 goals, third on the team behind Bo Horvat and Matthew Schaefer. Heineman’s 1.17 AB score put him right at the replacement-level league threshold, but his offensive production is indicative of a serviceable, young NHL player. He was the lone immediate NHL piece in the Noah Dobson trade with the Montreal Canadiens, perhaps Darche’s biggest managerial decision in his young GM career. Trading Noah Dobson at the time was considered a risky move. A 26-year-old stud offensive defenseman who shoots right-handed doesn’t grow on trees, as Montreal locked him up to a massive 8-year, 9.5 million AAV contract immediately following the trade. Along with Heineman, Darche acquired two first-round picks, which were used to select arguably the organization’s top two prospects: Kashawn Aitcheson, who just won OHL defenseman of the year, and Viktor Eklund, who had 10 points in his first 9 AHL games with the Bridgeport Islanders this season. This trade is a perfect example of Darche’s immediate ability to identify value in the trade market, as well as in creating opportunities for a youth movement on the Island. One could argue that Matthew Schaefer wouldn’t have had the immediate impact he did if Dobson still occupied a top-pair role. Schaefer stepped into his minutes, and the increased responsibility from the outset was a positive catalyst for his development, which is a silent yet evident part of the return from the Dobson trade.

Darche also gave his team an opportunity to push for the playoffs by acquiring a stable veteran presence in Brayden Schenn, without taking away from the Islanders’ own stash of draft picks or prospects in the process. They gave up the Colorado Avalanche’s 2026 1^st round pick acquired from the Brock Nelson trade under Lou Lamoriello, as well as a 3^rd round pick the Islanders acquired to take on Ondrej Palat’s salary from the New Jersey Devils. Schenn brought a Stanley Cup-winning pedigree to the team, as well as leadership that cannot be measured. His +1.20 AB Score places him above the league-replacement threshold, and he’s under contract until 2028-2029, meaning these assets weren’t traded for a rental but for someone who can be part of this team for the foreseeable future, helping to usher in a new crop of young Islanders as well.

What makes this roster construction especially interesting however, is that although a significant portion falls below league replacement, several have contracts expiring this upcoming offseason. Darche brought in players like Maxim Shabanov, Marc Gatcomb, and Adam Boqvist to cheap, low-risk, one-year deals, and traded for Carson Soucy on an expiring deal for the playoff push as well. These players, along with Anders Lee’s $7 million, will be off the books this summer. Combined with an increase in the salary cap to $104 million, this should give the Islanders some financial flexibility as well.

The Salary efficiency data above reinforces the idea that the Islanders are actually in a strong position despite some uneven replacement-level dynamics. The majority of their contracts, when run through the HFFA Arbitration Analyzer tool (for more information on the tool, please refer to the appropriate section of this article, There’s Something Special Going On In Utah, Why The Mammoth Are Here To Stay – hockey free for all.com (HOME OF THE ADVANCED BRACTON)). Due to the outstanding contributions of Matthew Schaefer performing as almost a $6 million player as an 18-year-old, in addition to Calum Ritchie making the best of limited minutes, the Islanders generated $13.23 million in surplus value according to the model, projecting a roster value of $102.9 million compared to the actual payroll of these skaters, resulting in $89.67 million. This indicates the Islanders are getting substantially more production than they’re paying for, another testament to management’s strong start evaluating the roster and keeping existing fair deals in place rather than moving them.

As previously mentioned, the salary cap flexibility and the fact that the Islanders can completely reshape the bottom half of their roster simply by not re-signing several of their below-replacement-level players in free agency provide for an intriguing offseason. Based on the Dobson trade, it’s reasonable to infer that Darche and his team will strategically manage to give their organizational youth every opportunity to make the opening night lineup this October. Cole Eiserman, Kashawn Aitcheson, and Calum Ritchie could be knocking at the door for full-time NHL status, and it’ll surely be interesting to keep up with their updates this upcoming summer.

When we look at the roster construction, salary cap configuration, move history, and prospect pipeline, Darche’s approach becomes clear. He didn’t attempt to rebuild or retool the roster in one year; instead, he created flexibility, redistributed opportunity, and smartly identified undervalued contributors. His intelligence led to an improvement in the standings, an accelerated development path for his franchise defenseman, a sizeable coaching upgrade, and a manageable salary-cap situation heading into an interesting offseason. In one year, Darche has positioned the Islanders not only to be competitive ahead of schedule but also to take a significant step with the right moves this offseason. It’s the beginning of the Islanders’ transition towards Darche’s long-term vision, which makes for an exciting next several months for Islanders fans. If his early decisions are any indication, the Islanders have the right man for the job to take them towards the next level of sustained contention.