PITTSBURGH (AP) The who and the when in the GOP veepstakes are still unknowns.

Presumptive Republican presidential nominee John McCain told KDKA NewsRadio in Pittsburgh that he hasn't decided yet on a running mate.

McCain is expected to name his vice presidential pick this week possibly tomorrow to create momentum heading into next week's Republican National Convention.

The Arizona senator has a rally planned for Saturday in Pennsylvania at which both former Governors Tom Ridge and Mitt Romney are scheduled to appear. But McCain cautioned against assuming that meant either one would be the pick.

Other names said to be on McCain's short list are Minnesota Governor Tim Pawlenty and Democrat-turned-independent Senator Joe Lieberman.

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