Should I start Clinton Portis, Reggie Bush or Chris Johnson in Week 2?

Bush is going against the Redskins, Portis is going against the Saints and Chris Johnson is going against a horrible Bengals defense. None of these teams have a good defense, but who do you think will do the best? I get fantasy points for carries, rush yards, TD's, recieving yards, td's and receptions...That's why I am thinking reggie bush