I have to say I don't at all remember him talking about considering early retirement. I recall him being upset he was traded:
Offensive lineman Max Unger admits that he was initially annoyed at being traded to the New Orleans Saints by the Seattle Seahawks. : american football new orleans saints transfer talk news unger was annoyed with trade decision 211693
amp.sportsmole.co.uk
And I recall that around that time there were many players around the NFL speaking out on concussions and player safety and that Max, being a vocal leader on the team was maybe one of them. Just don't remember there being a fear on his part or the Hawks that his career might be shortened.
And I still don't know why from an x's and o's perspective they made the trade in the first place. It made no sense then. Makes no sense now.
Harvin, head-case aside, I could understand. He was electric. Kick return, punt return. Out wide, in the slot. Jet sweeps... he was a dagger.
Jimmy for Unger?
I think the shift in power away from the LOB and Lynch and to Russ and his future 'crew' was a factor.
But maybe you're right.