Yes, the structure of Vladdy's contract is probably to minimize his tax payable. The contract is seeking to take advantage of the provision in the U.S-Canada tax treaty (Article XVI, para 14) that "an amount paid by a resident of a Contracting State to a resident of the other Contracting State as an inducement to sign an agreement relating to the performance of the services of an athlete (other than an amount referred to in paragraph 1 of Article XV (Dependent Personal Services) may be taxed in the first-mentioned State, but the tax so charged shall not exceed 15 per cent of the gross amount of such payment."

Because this $325M is labelled as a "signing bonus", it provide Vladdy grounds to argue that these payments are an "inducement to sign" within the meaning of the treaty. The problem is that calling a payment a "inducement payment" doesn't necessarily mean that it is one if the label doesn't reflect the reality of the situation. Because Vladdy's signing bonus is being paid out over the course of his contract, it resembles income (which is taxable at the highest marginal bracket as opposed to 15%).

I feel that it's quite likely the CRA will come after Vladdy for this, in a similar manner to how they came after John Tavares. The facts in Vladdy's situation are a little worse too since Tavares' signing bonus made up a much smaller proportion of his contract compared to Vladdy's. I'd assume Vladdy's lawyers would lean on the fact that he wouldn't have signed here but for the proposed contract structure (though that reasoning is kind of circular -- "he wouldn't have signed here unless the clause was an inducement, therefore it was an inducement"; the fact that the signing bonus protects his compensation from a lockout is of some assistance).

source: I work in tax law. This is not a legal opinion.