Erik Karlsson may not be among the NHL's top 2018 free agents, but he might be the most coveted player outside of prized New York Islanders captain John Tavares.

Dangled at the in-season trade deadline, the five-time All-Star defenseman has long been a speculated target with the Ottawa Senators in rebuild mode -- especially so now that teammate Mike Hoffman has already been dealt. And it's the Vegas Golden Knights, this year's biggest surprise Stanley Cup contenders, who are reportedly honing in on the two-time Norris Trophy winner.

TSN's Mike Kelly reported Friday that the "likely scenario for Erik Karlsson" is that he "gets traded to Vegas with Bobby Ryan sooner rather than later" and the Senators, in turn, "look to free agency" to fill their subsequent blue-line hole.

Ryan, the Senators' 31-year-old right winger, would make a potential Karlsson deal even more notable, although that's mostly because of his expensive seven-year, $50-million contract -- a cap hit Ottawa has reportedly been looking to unload for a while.

It remains to be seen just how far along any reported Karlsson or Ryan deal really is, however.

Despite Kelly's suggestion that Vegas, which is among the NHL's leaders in projected cap room, is in line to land the Senators' big-name defenseman, Sportsnet's Elliotte Friedman also said recently that "things have been very quiet on the Karlsson front" and that trade talks have "been a little softer than they would have hoped," in part because teams "know that they can play hardball" with the Senators.