A year ago there was a lawsuit brought by Karmanos' (owner) sons against him for $100M because he borrowed that money from the trust fund he set up for his kids for some purpose. It was never disclosed what the money was used for and a number of Quebec sports rags purported that it was for hockey operations. Never confirmed, just rumored. Anyway, the suite was settled, I believe with the settlement not disclosed. That, though, has nothing to do with an internal cap/budget. The Canes have always operated with an internal budget (all teams do) that has sometimes been lower than the Cap, but not always. That has never precluded them from making long term signings. What you will probably see, however, is that unlike some other clubs that massively front load contracts with bonuses, the Canes don't do that. I suspect you'll see that in this contract. In fact, I'd guess that you might see Slavin's contract escalates the actual salary over the course of the contract like Faulk's contract did.
On an aside, I think the lack of signing bonuses is one reason you don't see many high profile UFA signings here in Carolina.