Boldin can probably play until he's 40 due his kind of game.
Until and unless Fisher allows the ball to be thrown around with some alacrity, there is no point of bringing in a historically productive WR. Boldin would just be frustrated on the Rams and no doubt express it.
Rather we need FAs like Britt who are just happy to have a job and know that they could only get the kind of money they're being paid from Fisher where being a good teammate and trying hard counts for more than actually producing something.
