Here's what the Ottawa Senators should get for Erik Karlsson

Erik Karlsson is a generational defenseman who could be the difference between a team challenging for a championship and winning one -- and he's only 27. Richard A. Whittaker/Icon Sportswire

What return should the Ottawa Senators get in an Erik Karlsson trade?

Greg Wyshynski, senior writer: As incredible as it might have seemed a year ago, Erik Karlsson's departure from the Senators is starting to seem like an inevitability.

He loves the city. He loves the franchise. But the toxicity of the team's current state might be too much for the 27-year-old defenseman to overcome, from the team's downshift into a rebuild to the abject mismanagement of owner Eugene Melnyk. How does one accept a max contract offer while his team is slashing payroll everywhere from on the ice to in the front office to around the arena?

So it's a matter of time before Karlsson is traded, as Travis Yost spells out in his thorough breakdown of the situation here. When Karlsson goes, what should the Senators expect back for him?

That all depends on what they send with him.

Senators forward Bobby Ryan has what amounts to an untradeable contract: a $7.5 million cap hit through 2022, with a no-trade clause that covers 10 teams -- for a 30-year-old player with 20 goals in his past 101 games. There was talk that the Senators would hitch Ryan's contract to any Karlsson trade, and that makes sense from an Ottawa perspective. But it also means that the Senators need to find a team with $14 million in cap space to facilitate this package deal.

That nearly assures that the Senators will take some money back in a trade, so let's begin there: Ottawa will acquire a roster player with a robust cap hit who hopefully isn't signed through 2022. It will receive at least one first-round pick, and likely more than that. One assumes it will receive a blue-chip prospect as well.

Whatever team gets Erik Karlsson will be getting a generational defenseman who could be the difference between challenging for a championship and winning one. Or, dropping down a level, going from being a burgeoning contender to being a legitimate threat.

At the risk of being a total homer here: The New Jersey Devils have first and second rounders for the next three years, Damon Severson signed at $4,166,66 through 2023, a handful of prospects and $19 million in cap space. Oh, and Bobby Ryan is a Jersey native. Just sayin' ...

Emily Kaplan, national NHL reporter: Let's consider some recent blockbuster trades, beginning with last season, when the St. Louis Blues unloaded impending unrestricted free agent Kevin Shattenkirk on the Washington Capitals for a first-round pick, a conditional second-round pick and center Zach Sanford. In 2014, the Tampa Bay Lightning sent Martin St. Louis to the New York Rangers in exchange for a first rounder, Ryan Callahan (the captain and a fan-favorite grinder, but also a soon-to-be unrestricted free agent) plus a conditional second-round pick. That season also featured the Buffalo Sabres sending Thomas Vanek to the New York Islanders at the cost of a first-round pick, a second-round pick, and Matt Moulson (this was before Moulson's steep regression).

These all should be used as a baseline for what Karlsson would command. And I mean baseline. To have an elite, franchise-changing, puck-moving defenseman available at age 27? Yeah, general managers would give up a lot. Not to mention, Karlsson has another year on his contract, which is extra enticing. (He also has a modified no-movement clause and 10-team no-trade list; so either he's going to one of the 20 teams he approves or is waiving it, but either way, should be amenable to opening long-term extension talks.)

Part of the price is conditional on what the Senators would give. Retaining some of Karlsson's salary is an option, Remember, the Blues retained 39 percent of Shattenkirk's 2016-17 salary.

I keep going back to the initial asking price for Evander Kane: reportedly a first-round pick, a prospect, a roster player and a conditional pick. No teams have taken a bite, because that seems astronomically high for a player like Kane, who will be an UFA in July. I think that's the minimum for Karlsson. A first-round pick is non-negotiable. A second-round pick as an add-in doesn't seem outlandish. The prospect must be a legitimate one who can make the roster in the next two seasons -- I'm talking a top-two prospect in a team's farm system -- and maybe it's two prospects. The roster player better be ready to play right away, because we all know the Senators are going to need all the help they can get if they lose a player like Karlsson.

Chris Peters, NHL prospects analyst: I don't know that a package exists that would fully satisfy a Senators fan when it comes to potentially losing their team's generational defensemen. Few players can change a game the way Karlsson does. The Senators are going to have to get more than picks and prospects for him, that much is certain. I also think that this is the kind of deal the team is going to need more time to put together.

With Karlsson eligible to sign an extension this summer, it would be interesting to see what the Senators can do closer to the draft. That's not to say it has to be done that way, as Ottawa could arguably get even better value for him from a team that's in the playoff hunt and has the space to make it work. I just think the Senators might be able to work on things under less duress closer to the draft than they can near the deadline, because they must not mess up this trade as an organization. That said, since we're so close to the deadline, let's have some fun. Emily brought up some good recent examples of trades to consider when putting value together, but I'm going to go a little further back.

I think the deal that sent Ilya Kovalchuk from the Atlanta Thrashers to the New Jersey Devils in 2010 might also give us something to think about in this scenario. Kovalchuk was in his age 26 season on an expiring contract when he was traded. Karlsson is 27, but having that extra year of team control only increases his value, so it's definitely not a straight comp, but it gets us in the ballpark. Kovalchuk, Anssi Salmela and a second-round pick that became now-Vegas Golden Knights defenseman Jon Merrill went to New Jersey. The Thrashers got an established defenseman in Johnny Oduya; a reasonably solid young depth player who didn't end up taking the next step, in Niclas Bergfors; and a prospect who didn't end up panning out, in Patrice Cormier. The best part of the trade, however, is that Atlanta got a first-round draft pick and a second-round pick that ended up being packaged in the trade that brought Dustin Byfuglien to the organization -- where he became a star for the Thrashers and then the Winnipeg Jets.

While you never know how a trade is going to work out, Pierre Dorion has to be asking for the moon here, much like the Thrashers did when they dealt the face of their franchise, who had already scored 31 goals that season. A lot has changed in the eight years since that trade, but the Senators need something massive in return to even come close to matching Karlsson's value. Collecting as many assets as possible, including one or two players who could be in the lineup right away, could give Dorion a lot of options to maximize the trade, too.