Obama praises Sen. Evan Bayh but not as VP

Bayh, once a two-term governor of Indiana, was a big supporter of Hillary Clinton during the primaries. Advocates of an Obama-Bayh ticket say he'd help unify the party and could shore up some of Obama's weak spots because of his time on the Senate Intelligence and Armed Services Committees.

"Evan Bayh is not the kind of person to make mistakes. He is loyal; he's trustworthy; he's smart; he looks terrific in a photo op," said Stu Rothenberg of the Rothenberg Political Report.

According to CNN's polling, Indiana and its 11 electoral votes are leaning toward Obama, but the senator from Illinois has not locked in the state.

Bayh tried to downplay the idea that Obama would need him in order to come out on top in Indiana, telling CNN that Obama is competitive in Indiana because of "what he stands for, who he is and the desperate need for change and a better direction in Washington."

Virginia Gov. Tim Kaine, Delaware Sen. Joe Biden and Kansas Gov. Kathleen Sebelius are also considered top contenders for vice president.