The New York Rangers and their young Norris Trophy-winning defenseman, Adam Fox, have agreed to a historic contract extension.

Fox, 23, signed a seven-year deal on Monday, taking him through the 2028-29 season. Terms weren't disclosed by the team, but a source tells ESPN the average annual value of the contract is $9.5 million against the NHL salary cap. He's in the last year of his entry-level contract this season.

The $66.5 million deal is the largest contract in NHL history for a defenseman leaving his entry-level deal.