Absolutely Jo Jo should keep his place. Given that he is also on a one year contract (I think) alienating him by dropping him would be a dumb move when it comes to tempting him to sign a new one. He is number one until form suggests otherwise. He got an international call up - dropping him for that, no matter ho good a game Ward had would be poor management in my view.
But the thing is, we don't know how good Ward is.
Both keepers have similar backgrounds and both may have benefitted from coaching with Mildy. I think that dropping Ward after that (an almost perfect game) would alienate him and show that no matter what he does, he is only ever the back up.
There is an ideal opportunity to keep both players happy at the moment. Play Ward again on Tuesday and see how he does. If he is as awesome as Saturday, you don't drop him for next Saturday.
In the mean time, you talk to Wollacott and praise him for what he has done so far this season and tell him to rest from the travel and get back to fitness in training. You let him see how brilliant Ward was on Saturday and you motivate him to battle for his place.
If Ward doesn't do so well on Tuesday and Wollacott looks sharp in training then he comes back in on Saturday. But if not, Garner has already shown with Grant that he will make the tough calls.