Everything in the next paragraph pertains to the season up until this point, or maybe until August.
With the amount of money B.J. is owed, you have to play him and let him try to figure it out. There's no way management will outright cut him with 3 yrs/$45 million left on the books. We're stuck with him, so we pretty much have no choice but to try to rehabilitate him and hope it works.
That being said, he should never, ever bat anywhere higher than 8th until he proves himself to be something other than what he's shown in his nearly 2 years here. And going forward, with the team being in a close pennant/wild card race, and with a better option now on the roster, B.J. should be limited to spot starts and pinch running. We have seen enough to know that he isn't going to get any better for the rest of the year, if ever.
I think the guys eyes are screwed up big time. He's missed some balls that should have been caught where it almost had to be a case of his eyes telling him the ball was in one spot when it was clearly somewhere else.