There are two basic ways for teams to reconfigure their rosters during the NHL offseason. The first is the time-honored tradition of overcompensating veteran players through unrestricted free agency while refusing -- through a gentlemen's agreement among general managers or outright fear of repercussions -- to dabble in restricted free agency for younger talent via offer sheets.
The other way is through the trade market.
In theory, a combination of both is the right recipe. Look no further than the Stanley Cup champions. The St. Louis Blues signed Tyler Bozak, David Perron and Patrick Maroon to free-agent deals prior to last season, and then they swung for the fences with a multiplayer deal for Ryan O'Reilly, whom you may remember from winning the Conn Smythe Trophy.