I don't think they can actually spread out the salary from the three years initially offered. They just get the last two much cheaper.If they offer a 5 year deal straight up and structure it that way it’s fine, but not when they offer a 3 year free agency deal with 90% of the salary that he gets over 5 years and the two year extension comes after he signs.
The problem here is they’ve, maybe, offered a mammoth deal over 3 years to (potentially) manipulate the free agency compo and get ESS a better pick so they don’t match, then extend the contract at very very low cost to spread his salary out over 5 years.
They may not have done this, but that the question that’s being asked.
They'd probably get away with it without question if they extended him in the third year, instead of now.