There's no indication of how Karlsson reacted to the offer, but a report from Larry Brooks of the New York Post on Monday revealed the Senators have given clubs across the league permission to negotiate an extension with the two-time Norris Trophy winner.
Karlsson's current contract is set to expire after the 2018-19 season, and he could've been joined in a star-studded class of unrestricted free agents by Drew Doughty, arguably the only blue-liner held in the same regard. However, the Los Angeles Kings stalwart agreed to terms on an eight-year deal worth a reported $11 million annually, which would make him the NHL's highest-paid defenseman.
In November, Doughty said he and Karlsson would discuss what kind of money they'd be looking for in an extension.
With the big names off this summer's free-agency board, Karlsson's future is the offseason's top story, and his potential departure from Ottawa after nine seasons with the club would significantly alter the team's trajectory.