I disagree. I think they would've brought him back for another season. 1 year, whatever is left of the cap the day before th season starts would've been his contract.
They just haven't done anything to indicate they would want a spot tied up with a 38 year old Brown. If he was still signed for next year, like there had been a 9th year on the deal, sure, they're not buying him out or anything. Too much respect for him and what he meant to the franchise.
I think both sides were, yeah, I'm good. Brown isn't chasing anything. He rarely if ever looked like a player this season who wanted to do this another time. Him gone opens up a spot for someone younger. Someone hungrier. I would guess nobody was saying, come on Dustin, we really need you for another year.
They probably met sometime, Brown says you know Mr. Bosses, I think I'm done. Then they say, that's cool, bro. Appreciate everything.