Prediction

Obama will dump Biden and pick up Hillary as his V.P. choice in October (or perhaps sooner)

Of course, his campaign will never admit that they dropped Biden. No, it will be announced that Biden has decided that he just isn't up to the job, and that he is doing what is best for America and stepping aside.

His latest statements were made just to prepare us for it. Why else would he say something like this?

Biden: Hillary Might Have Been Better VP Choice