Playing chicken on VP announcements

The "McCain will name his VP" mantra is still going on, properly seeded by the McCain campaign to get a WaPo frontpager today, "He's in a position to make [the decision] on short notice if he wanted to," said Charles R. Black Jr....," but I wonder how much of this is about a game of "chicken" with Obama.

Because of the way the calendar lays out, next week is really Obama's best window to name a VP. Reading this last round of McCain VP speculation, I wonder if the McCain campaign is trying to affect the timing of Obama's announcement.