The Montreal Canadiens and the Nashville Predators exchanged No. 1 defensemen in search of the perfect fit for their respective teams.
In Shea Weber, the Montreal Canadiens received an experienced defender who can handle all the tough minutes that are assigned to him, and who has one of the most dangerous shots in the League.
In P.K. Subban, the Nashville Predators got a younger defenseman (27, compared to the 30-year-old Weber) with superior playmaking skills, and the ability to drive possession.

Regardless of their playing styles or which uniform they wear, Subban and Weber are two of the game's best defensemen. Subban won the Norris Trophy for the 2012-13 season and was third in 2014-15, and Weber placed second in 2010-11 and 2011-12, third in 2013-14, and fourth in 2008-09 and 2014-15. Subban was named to the First All-Star Team in 2012-13 and 2014-15, and Weber in 2010-11 and 2011-12. They will continue to have a big impact no matter where they play, or how they are used.

A closer look behind the numbers can help find subtle but key differences between these two game-changing defensemen.
Scoring Style
In traditional scoring terms, there's very little difference between Weber and Subban. During the past six seasons, Subban has 276 points and is a plus-34 in 432 games, and Weber has 277 points and is a plus-32 in 443 games.
The primary difference is that Montreal swapped a top playmaking defenseman for a top goal-scorer.
Subban is one of two defensemen with at least 43 assists in each of the past three seasons; the other is Erik Karlsson of the Ottawa Senators. Added together, Subban's 133 assists are tied with Keith Yandle of the Florida Panthers for second behind Karlsson's 165 in that stretch.
Weber never has had more than 33 assists in a season, but he has had at least 30 six times in the past eight seasons. In that span only Ryan Suter of the Minnesota Wild and Duncan Keith of the Chicago Blackhawks have hit that mark more often (seven times).
In goal-scoring, Weber has the edge. He is the only active defenseman with three 20-goal seasons, and his 58 goals over the past three seasons combined ranks third among defensemen behind Brent Burns of the San Jose Sharks (66), and Oliver Ekman-Larsson of the Arizona Coyotes (59).

Shot Attempts
Nashville's shot-based metrics should get a big boost from Subban, who is one of the strongest possession-driving defensemen in the League.
During the past six seasons the Montreal Canadiens outplayed their opponents 7,388 shot attempts to 6,811 with Subban on the ice, for an SAT of plus-577. The next best Montreal defenseman (at least 50 games played) was Andrei Markov at plus-138.
To put it in other terms, the Canadiens have been responsible for 52.0 percent of all on-ice shot attempts when Subban has been on the ice, and 48.1 percent when he has not. That difference of 3.9 percent ranks No. 9 among the 278 NHL defensemen to play at least 100 games during that time span.
Instead of driving possession, Weber's main contribution in Nashville has been to handle all the tough minutes while his younger teammates developed.
Subban and Weber have been their team's top choice, regardless of man-power situation, zone, opponents or the score, but the tough minutes were spread more evenly in Montreal. With Weber's arrival, Montreal now can develop its next generation of defensemen by leaning more heavily on him.

Larger Windows
The simplest difference between the two players is their age. When the puck drops next season, Subban will be 27, and Weber will be 31 (his birthday is Aug. 14).
That may not be a significant difference for a single season, but it should give Nashville a larger window in which to receive maximum value before a player's performance starts to naturally decline.
Furthermore, Weber is under contract for 10 more seasons. Subban carries the greater annual salary-cap charge of $9 million vs. Weber's $7.86 million, but Subban is signed for six more seasons. The Canadiens save cap space in the short term, but the Predators gain more long-term cap flexibility.