There is interest in Erik Karlsson from opposing teams, but the Penguins don't want to give him away for nothing.
For the right price, I believe he will be traded. The Penguins are willing to retain some of his salary. They realize he's not part of the future in Pittsburgh and that the experiment hasn't worked.
However, trading him remains complicated. I don't see him playing out the final two years of his contract in Pittsburgh. Dubas would like to get a good return for the future Hall of Famer, whose value around the NHL varies widely based on whom you ask.