General manager Brian MacLellan released a statement about the move:
"John has been an exceptional and consistent player for our franchise and has blossomed into being one of the top defensemen in the NHL. Defenseman like John are a rare commodity in our League and, at 28 years of age, we feel he is just entering his prime. As a right-handed defenseman, John plays in all key situations and has contributed greatly to our team's success on the special teams. We are pleased for both parties to have come to an agreement and for him to continue his great career as a Washington Capital."
According to Spotrac, Carlson's new contract makes him the second-highest-paid defenseman by average salary alongside Brent Burns. Only P.K. Subban ($9 million) has a bigger salary-cap hit.
The stars aligned for Carlson's payday.
He finished with a career-high 68 points (15 goals, 53 assists) in the regular season and helped the Capitals win their first Stanley Cup title. Carlson delivered in the postseason, scoring five goals and assisting on 15 more.
Considering how important he was to the Capitals, Carlson getting a new deal from Washington appeared to be the most likely conclusion this offseason. Sportsnet's John Shannon noted the Capitals' trade of Brooks Orpik and Philipp Grubauer to the Colorado Avalanche cleared the way for a big extension:
The deal now creates two questions, one of which applies to the league as a whole and the other more pertinent to the Capitals.
For one, it could set the free-agent market for the top defensemen. Drew Doughty and Erik Karlsson are two of the top players at the position entering the final years of their contracts in 2018-19:
Then there's the matter of whether Carlson's contract hinders Washington's financial flexibility going forward. Andre Burakovsky and Jakub Vrana are restricted free agents in 2019, and Nicklas Backstrom and Braden Holtby are out of contract in 2020.
With their championship window open right now, meeting Carlson's demands makes sense. But it could mean sacrificing one or two key players in the future to ensure the team stays under the salary cap.