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: 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.

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 salary cap was $79.5 million this past season, and there are fears that the new cap, which takes effect July 1, will be under the $83 million initial projection.

Still, 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.”

Might a trade for Nashville’s P.K. Subban fit for New Jersey? The Devils not only have more than $30 million in cap space but a surplus of young forwards and prospects.