In case you missed Wednesday big news, the Vegas Golden Knights signed 27-year-old forward Jonathan Marchessault to a six-year contract extension with an average annual value of $5 million.Not a bad price to pay for a guy who been playing like one of the top forwards in hockey.When our own Danny Webster asked Golden Knights general manager George McPhee about Marchessault extension, though Malcolm Subban Jersey, he gave a bit of an interesting answer.George McPhee on signing Jonathan Marchessault to his new extension "He fits our identity of a guy who competes on both ends of the rink, and he's generating offense. We like how the line he's on is performing and wanted to keep it together."— Danny Webster January 3, 2018Marchessault and Reilly Smith are both under contract through the 2021-22 season. Center William Karlsson, however, the third member of the aforementioned Marchessault line, will become a restricted free agent this offseason. So if McPhee wants to keep that line together long-term, Karlsson will need to be signed to a contract extension as well.Without a doubt, Karlsson will be looking for a deal close to the value of Marchessault contract, which is certainly warranted. After all, he leads the Golden Knights with 20 goals through just 38 games and is on pace to shatter all of his previous career highs in every major statistical category Vegas Golden Knights Shop.Luckily, the Golden Knights should have more than enough cap space to lock up the 24-year-old Swede long-term. Even after Marchessault contract extension, Vegas is still projected to have a solid $8 million in available cap space this offseason, per CapFriendly.And regardless of price, the Smith-Karlsson-Marchessault line has been so good that breaking it up would be almost asinine. That line has been one of the very best in the NHL this season and splitting it up would put a major dent in Vegas’ offensive efficiency.Nobody saw it coming prior to the season, but Karlsson has cemented himself as one of the Golden Knights’ core players. And from where we stand right now, he appears to be the odds-on favorite to earn the next big extension.Stay tuned.