Rob Vollman is a pioneer in the field of hockey analytics and the co-author of Hockey Abstract. His innovations include Player Usage Charts on Home Plate Save Percentage. He will contribute a regular column to NHL.com throughout this season.

When the Dallas Stars played the Buffalo Sabres on Tuesday, it was a game between the NHL's two most improved teams.

It ended with a 3-1 Dallas victory, denying Buffalo a chance to go over .500 for the first time since Jan. 24, 2013.

Buffalo's 8-9-1 record is a big improvement from the three previous seasons, when it stood at 6-11-1, 3-14-1, and 3-13-2. More importantly, it is good enough to be squarely in the mix in the tight Atlantic Division.

In terms of goal differential, the Stars' two-goal victory earned them the distinction of being the only team to improve by a wider margin than the Sabres this season, relative to where teams were on Nov. 18, 2014.

Top 5 Teams by Goal Differential Improvement 2014-15 2015-16 Team GF GA Diff GF GA Diff Improvement Stars 48 60 -12 68 48 +20 +32 Sabres 28 67 -39 40 49 -9 +30 Rangers 49 54 -5 56 31 +25 +30 Canadiens 51 47 +4 67 41 +26 +22 Avalanche 45 59 -14 50 50 0 +14

After years of familiar faces on the ice, behind the bench, and in the front office, the Sabres have undergone a complete overhaul during the past three seasons. At first, the rebuild didn't go smoothly, with the Sabres finishing last in the League two seasons in a row, losing the NHL Draft Lottery on each of those occasions. Now, thanks to its organizational strength beginning to bear fruit, its notable upgrade with coach Dan Bylsma, and new GM Tim Murray's shrewd late-season and summer acquisitions, Buffalo is a competitive team again.

Let's break down the numbers behind each of those factors:

Organizational strength

The Sabres have been ranked near the top of the League for years. Most recently, Hockey's Future ranked them sixth, and those who rely more on statistical analysis, like Bleacher Report's Jonathan Willis and ESPN's Corey Pronman, ranked them even higher, second and third, respectively.

NHL.COM ENHANCED STATS View Buffalo Sabres SAT% leaders



At last, many of those top prospects are becoming NHL regulars, including most notably their No. 1 defenseman Rasmus Ristolainen, centers Jack Eichel and Zemgus Girgensons, and wing Sam Reinhart.

It's not always easy to predict which players will succeed at the NHL level, but the sheer number of blue-chip prospects in their system gives the Sabres a huge upside. Most importantly, Murray made a summer priority out of finding a coaching staff that could unlock the enormous potential.

Coaching upgrade

The impact of a coaching staff is often overlooked, but going from a relatively untried NHL coach like Ron Rolston and journeyman Ted Nolan to two of the most experienced and accomplished coaches in the League can have an enormous impact.

Bylsma and assistant Terry Murray have 1,431 combined games of NHL coaching experience, which ranks fifth among the League's coaching staffs. When comparing how well their teams have done relative to the previous season, no coaching staff in the NHL has had a greater combined history of improvement in the standings than Bylsma and Murray. Among those who were available this summer, they are the ideal coaches for Buffalo's current situation.

Career Experience and Success of NHL Coaching Staffs Team Coaches with NHL Experience NHL Games Coached Points of Improvement Chicago Blackhawks Quenneville, Dineen, Kitchen 1,670 -40.8 Dallas Stars Ruff, Fraser 1,627 -9.9 St. Louis Blues Hitchcock, Muller, Shaw 1,568 +49.3 Los Angeles Kings Sutter, Stevens, Payne 1,543 +46.8 Buffalo Sabres Bylsma, Murray 1,431 +62.6

With Punch Imlach, Scotty Bowman, Roger Neilson and Lindy Ruff, the Sabres have a proud tradition of great coaching. Bylsma and Murray have all the skill and experience required to get the most out of their prospects and the new players on the roster.

Murray's acquisitions

Since being named the Sabres' seventh general manager on Jan. 9, 2014, Murray has taken slow and steady steps to restore their competitive balance.

Up front, Murray recrafted the top line by acquiring Evander Kane from the Winnipeg Jets on Feb. 11, 2015, followed by the acquisition of No. 1 center Ryan O'Reilly from the Colorado Avalanche on June 26. The former supplements Matt Moulson's goal scoring on the left side, while the latter can play the tough minutes, which allows the young centers to be brought along more carefully. Murray also acquired some depth by adding Jamie McGinn in the Colorado trade, and trading for versatile free agent David Legwand on July 5.

On the blue line, Zach Bogosian was acquired in the Winnipeg trade and made his season debut against Dallas after missing the first 17 games with a lower-body injury. Murray also signed free agent Cody Franson on Sept. 10, a player adored in the hockey analytics community for his strong puck-possession numbers and superb power-play scoring rate. Given Buffalo's youth, signing depth free agent defenseman Carlo Colaiacovo on July 3 was a shrewd contingency move.

There have also been big changes in goal, which is quite a departure for a team that had Ryan Miller as a fixture for almost a decade. In his short tenure as GM, Murray has acquired Jaroslav Halak, Michal Neuvirth, Anders Lindback, Chad Johnson and Robin Lehner, and called up Nathan Lieuwen, Andrey Makarov and Linus Ullmark. At the moment, it's unclear where the chips will ultimately fall, but the Sabres are in a far more flexible position in terms of salary-cap space, and with a far greater understanding of their options.

What should happen

Buffalo's improvement is truly remarkable, but it reflects a legitimate step forward, and the numbers suggest it should continue. Given all the new faces, including the Sabres' prospects and those who were recently acquired, and a coaching staff with the experience and prior success to unleash their combined potential, this early success was entirely predictable.

Will the Sabres make the Stanley Cup Playoffs this season? Probably not. This is a team that has been making all the right moves but simply began in far too deep a hole. However, if they stay on track, the Sabres will soon return to playoff contention on a regular basis.