It's hilarious you keep mentioning this like it's annually...and they already paid him that money whether he's there or not so it has zero impact on negotiating.
Well it is the 2015 season. So it counts against your cap this year. Perfectly relevant when discussing what the Pats have invested in him this year if he happens to resign.
Plus if he was to formulate a deal before the option expires they would still have to spread that $5M out over the contract to reduce his 1st year cap hit to something more manageable. Unless they do straight bonus money. Then it's less of a factor. Problem is you start with a $5M disadvantage with not a lot of money to start with on your cap.
You act like that money doesn't matter since it was paid out. It certainly does matter when you are trying to resign a guy and manage your cap.