Matt Niskanen wasn't totally shocked when the Washington Capitals traded him to Philadelphia last week.

One look at their salary cap picture explained it.

"I know what kind of situation Washington was in, so I knew there was a possibility," he said.

General managers say there is more trade chatter now than at any time in recent years, and much of it has to do with a wide gap between the haves and have nots across the NHL. Only it's not about contenders and rebuilders; a handful of teams know they will be up against the salary cap ceiling and many others have plenty of room and can use it to take on bad contracts to get better.

The NHL trade market is heating up. Follow the money to see where it goes.

"One thing I think is really apparent is that there's a commodity out there called the cap," Winnipeg general manager Kevin Cheveldayoff said. "I think that a lot of people are talking around those things as well. It's an interesting dynamic this summer, so we'll kind of see."

Cheveldayoff's Jets are on the selling side because they need to get new contracts done for budding star forwards Patrik Laine and Kyle Connor, and already have an established core signed to big-ticket deals. They traded defenseman Jacob Trouba to the New York Rangers on Monday and aren't done dealing.

"There's realities in a hard cap world," Cheveldayoff said. "There's no question we have a challenging summer still ahead of us."

The rebuilding Rangers are closer to the other end of the spectrum with almost $19 million in cap space to play with. They might be able to accelerate the climb back to the playoffs with some shrewd moves at the draft this weekend and beyond because they can spend to the cap and don't need to win this year.

"What we've learned over the last few years since we started on this rebuild is having cap space affords you conversations you couldn't have before," New York GM Jeff Gorton said. "Now I think we're in conversations and we're talking to teams about things that maybe three or four years ago we weren't able to do. There's a lot of different avenues to do this, and there's a lot of conversations that go into it as far as eating money or spending money or what you have to do. But definitely having cap space is a big thing ... it's a big weapon to have as we move forward in our rebuild."

The New Jersey Devils are in a similar spot. They are expected to take American center Jack Hughes with the first overall pick Friday — leaving Finnish winger Kaapo Kakko for the Rangers second — and might be a No. 1 defenseman and a few other additions from being playoff contenders again.

Might a trade for Nashville's P.K. Subban fit for New Jersey? The Devils not only have over $30 million in cap space but a surplus of young forwards and prospects that could make for an intriguing offer to the Predators, who look poised to shake things up after back-to-back early playoff exits.

Pittsburgh is among the contending teams that need to shed salary to be under the cap. The Penguins began that process by sending defenseman Olli Maatta to Chicago for young forward Dominik Kahun and a draft pick , and winger Phil Kessel would have been on the move to Minnesota had he not vetoed the trade.

GM Jim Rutherford said he's "trying to retool" on the fly and won't rule out trading someone like center Evgeni Malkin or defenseman Kris Letang.

"There's been great players traded in this league, and if somebody comes along with a package that makes sense for the Penguins, we have to look at it," Rutherford told 93.7-FM in Pittsburgh. "We're not finished making changes. I would expect that there will be a couple more before training camp starts."

The same goes for San Jose, which re-signed two-time Norris Trophy-winning defenseman Erik Karlsson to a $92 million, 11-year contract and already cleared some room by dealing veteran blue liner Justin Braun to Philadelphia. The Sharks still have to re-sign impressive young forward Timo Meier and would love to bring back Joe Thornton and captain Joe Pavelski.

Of course, there's only so much money to go around, which may force the Sharks to deal.

"Under a cap system, choices and decisions need to be made," GM Doug Wilson said.