I've always thought of Parish as a guy BB would like.
However, Ive never seen a lot of success in chasing guys who used to be good but have declined.
Analogy:
Most good safeties start out as something like Dexter Reid, grow into good players, then slide back down to being Dexter Reid again.
Of course the biggest failure with teams that go nuts in FA is that they pay the guy based on how good he was but they get Dexter Reid.
That wouldnt be an issue now, but it would be just as bad to bring him in expecting him to still be Tony Parish and find out on the field he has falled to Dexter Reid level.
I have however always felt that veteran DBs, and especially reserves who can come in in sub packages were a good fit in a BB defense because he can limit their role to what they do well, and hide their weaknesses. (See Otis Smith, Terrell Buckley, Victor Green, etc, etc).
I suppose he could help if for nothing else on special teams, because he has always been a good athlete, who plays big for a safety. I believe he has had a lot of Ints over his career too.