Marner does not seem like the type to leave millions on the table. Let's say he signs a 7 year deal, what would be his next contract when he's 35? Maybe 4 million AAV to be generous?
Now, I don't think Marner is making 12 million per on his next contract, perhaps a team will pay him 11.5 million per for 7 years if he doesn't sign with the Leafs...so that's 80.5 million over 7 years...if you add the 4 million to 80.5 million, you get 84.5 million for 8 years, so his AAV over 8 years is 10.56 million...if he extends with the Leafs for 8 years at 11.5 million per and is traded, he makes about 1 million more per year for 8 years...that's not chump change.
If the Leafs don't plan on re-signing Marner, it's really in his best interest to work out an extension for 8 years this summer and agree to a trade to another team who wants him instead of playing hardball or a game of who blinks first.