Who do you need more?
I suspect neither one will return before Sept, and neither team will push them to come back to help either. Both will likely be playing w/ some discomfort or whatever, assuming they return. If Bonds does return, he's probably more likely to be productive. I'd think Halladay's leg would bother him more than Bonds' knees if/when they first return.
Either way, don't expect much help from them.