Ten years from now, we may look at the P.K. Subban - Shea Weber trade in the same light as the Chris Chelios - Denis Savard trade of the early 1990s.

It's a grim assessment, but what's done is done. So given what we know about Weber's style of play and the facts surrounding his on-ice production, what can Montreal's coaching staff do to get the most of this useful, but imperfect player?

1) Shea Weber in a Nutshell

If you do not believe in the value of advanced statistics and are not interested in learning more about the numbers side of things, no worries.

Here's what you need to understand about Weber in very simple terms:

- He is a very good defenseman in static situations - if you need someone to clear out the front of the crease, or take a slap shot from the point with your entire attack set up, or even to make an intermission locker room speech if things aren't going well, Weber is your man. He thrives on playing and thinking in structure.

- He is not a very good defenseman in dynamic situations - if you need someone to stop an opposing rush by playing a tight gap at the red line, or to improvise with the puck under pressure in the defensive zone, or to make a pinch to keep an offensive play alive in the opposing zone, Weber's in trouble. He lacks the fluidity and imagination of a Subban, an Erik Karlsson or a Kris Letang. What he's missing can't be taught.

- Weber is not a puck possession defenseman. He'll let you touch the puck first, and then crunch you into the boards, which is why many NHL forwards are intimidated by his presence. But first he lets you into his D zone, which means you'll always have a chance to make something happen if you can sidestep him and find an open teammate.

These types of defensemen tend to not age as well (Ed Jovanovski, Brent Sopel, Douglas Murray, Roman Polak, etc.) compared to those who can anticipate the play and move the puck without body contact (Brian Campbell, Andrei Markov, Marek Zidlicky, Lubomir Visnovsky, etc.) because they do not have a Plan B if the wait-and-hit approach no longer works. In the modern NHL, if you own the puck, you direct the action.

I do believe that Weber is an elite NHL player at his position, but like soccer's legendary Franz Beckenbauer, perhaps he is playing a position which no longer exists.

I'm not entirely convinced whether Weber's strengths and weaknesses will cancel each other out in Montreal - his on-ice goal differential in Nashville has been right around team average for the past three years. But the above is the essence of the Weber question.

2) Weber's Impact on Montreal's Defensive Unit

The two players most affected by Weber's arrival are Andrei Markov and Jeff Petry - the former being Subban's most frequent partner, and the latter being his most frequent on-ice replacement.

In the past three seasons, Andrei Markov has been excellent playing alongside Subban. The pair accounted for 52% of shot attempts (Corsi) and 56% of goals when on the ice together at 5vs5, some of the best results for any full-time Canadiens defense pairing in that span. However, away from Subban, Markov has struggled, posting a 46.8% Corsi with Alexei Emelin and a 45.0% Corsi with Tom Gilbert, his next two most frequent partners. As you can see in the spider chart above (2015-16 only), Markov's possession numbers have taken a dive whenever he is not on the ice with Subban. At a team level, it's like going from playing like the Pittsburgh Penguins (52.7% Corsi last year), to playing like the Arizona Coyotes (46.8% last year).

Petry, meanwhile, has done well in his role in Montreal - that of a second-line defenseman who never needs to play with the best defenseman to be able to move the puck in the right direction. Petry struggled to meet expectations in Edmonton, where he was the only right-handed defenseman able to keep his team above water, but has blossomed with Subban taking on key matchups and a portion of his 5vs5 minutes.

With Weber replacing Subban, the 38-year-old Markov no longer has a partner able to prop him up and cover his weaknesses. As Weber declines, Petry (who, at age 28, is already in his prime) may not have the chops to take over in a bona fide number one role, either.

No NHL team can hope to be competitive, much less contend for the Cup, with a Top-4 in turmoil, but there might be a fit to be found with the defensemen currently at the Habs' disposition.

If I pulled the strings, I would start the 2016-17 season with the following duos:

Beaulieu-Petry

Barberio-Weber

Markov/Emelin-Pateryn

Beaulieu-Petry have controlled an incredible 58.2% of shots as a unit in the past two years, while the mobile Mark Barberio could be a good left-handed complement to Weber, who does not handle the puck nearly as much as other top NHL defensemen and who needs his partner to quarterback the breakout. Alternating Markov and Emelin will help keep both healthy and productive, and Greg Pateryn has proven himself to be a good, cheap sixth defenseman at the NHL level.

3) Weber and Offensive Deployment

If we look at Weber's possession stats in Nashville, we would see that they've varied wildly depending on which forward lines he played with. In 2015-16, Weber struggled when on the ice with Mike Fisher (#12) and Paul Gaustad (#28), the Predators' two defensive-minded centremen.

Meanwhile, he has been able to thrive when playing alongside Mike Ribeiro (#63) and Ryan Johansen (#92), the team's two offensive pivots. In Montreal, Plekanec and Mitchell have a very similar role to that of Fisher and Gaustad, facing tough competition in defensive zone starts, while Alex Galchenyuk and David Desharnais receive a more favourable offensive tilt by the coaching staff.

What I would do with this knowledge would depend on a few other factors. While Weber's strength and ability to play with defensive structure would be an asset in the Montreal zone, I would be wary to immediately give him a heavy dose of defensive zone starts against top-line competition. How best to deploy Weber would depend on his efficiency on zone exits, his ability to defend the rush skating backwards, and how he influences the shot differentials of Montreal forwards. We won't know until the season starts, but those would be the three metrics to keep an eye on.

4) Weber and the Power Play

From an article I wrote two years ago:

With 347 points in 607 career NHL games (0.57 point per game, compared to Subban’s 0.59), Weber ranks among the elite offensive blue-liners in the league. More importantly for us, his career shooting percentage is 8.1%, significantly higher than Subban’s 5.7% success rate. Last season, Weber led all NHL blue-liners with 23 goals on the strength of a career-best 11.8% shooting percentage. Both guys play the same position and have more or less the same offensive role on their teams. I don’t really buy the argument that Weber has a better shot, and definitely don’t think he's on the receiving end of better passes, so what accounts for that gap? While the even-strength data is inconclusive, we start seeing some serious trends once we get to the man-advantage stats. With the eye test, one is led to believe that Subban and Weber have a similar way of running the point, patrolling the right side of the ice off the faceoff before switching sides with their partners and loading up on their fearsome one-timers. Instead, there are two important distinctions between Weber and Subban, both of which have helped the former score 10 more goals than the latter over the course of the 2013-14 season... The big difference in the results of Montreal and Nashville’s number one power-play gunners relates to their tactics while stationed at the traditional point position. Subban seems to use the blue line as a reference and let it rip whenever he has an opening, Weber’s favorite place to set up his one-timer is right at the top of the left circle, about 35 feet out... Assuming both players square up and unleash a 90mph slap shot, Subban’s try from 60 feet out would reach a Henrik Lundqvist or a Tuukka Rask in about 0.46 seconds, while Weber’s identical shot from 35 feet away would go from stick blade to net in 0.27 seconds; 42 percent faster. In a league where goaltenders are as good as they are, it can mean the difference between an easy save and a game-winning goal. Perhaps not coincidentally, Montreal’s power play was 19th best across the NHL in 2013-14 with a 17.2% success rate. Meanwhile, with a much less accomplished collection of players, Nashville managed to finish 12th overall, scoring on 19.2% of man-advantage opportunities.

While Weber's superior shooting prowess on the power play will not be captured in his possession and goal differential stats (which only reflect even-strength play), him scoring a dozen goals on the man advantage would go a long way towards bridging the gap in value between he and Subban.

Pacioretty

Weber-Gallagher-Galchenyuk

Petry

If the Montreal coaching staff decides to give the 1-3-1 powerplay formation another go, having Weber set up as the trigger man near the left sideboards may finally yield a top-five power-play unit in the NHL.

Postscript: The Law of Unintended Consequences

In my view, the only chance for the Habs to get as much production out of Weber than it had received from Subban is for the former to be utterly dominant as a power-play shooter. The problem with that is NHL teams still overpay for power-play production in UFA and RFA contract negotiations. If Galchenyuk, Gallagher and Pacioretty accumulate a large number of power-play assists by passing the puck to Weber, they might be even harder to keep a few years down the road.

Basically, the Habs' decision-makers have put themselves in a no-win situation. If Weber pans out and is able to turn the Habs into a contender, there will be an even-more-serious-than-expected cap crunch in the near future. If Weber turns out to be a flop, the consequences will be no less disastrous. Time will tell if the subjective factors which led to Subban's trade will negatively affect the career prospects of those involved in the decision. Possibly the best move at this point is to trade futures and to overpay for players who can help the team now, and hope for the best between now and when Carey Price's contract ends.

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Jack Han is the Video & Analytics Coordinator for the McGill Martlet Hockey team. He also writes occasionally about the NHL and hockey analytics for Habs Eyes on the Prize and HockeyGraphs.com. You can find him on Twitter or on the ice at McConnell Arena.

(possession stats via Corsica.hockey and stats.hockeyanalysis.com)