"Would I like to win by double digits? Sure," said Rendell, a Clinton supporter. "But I don't think that's going to happen in Pennsylvania."
U.S. Senator Bob Casey, an Obama supporter who also appeared on the show, said the Illinois senator has made "tremendous progress" over the last six or seven weeks.
"I think his message of hope, his message of change, has resonated, but we'll see what happens," Casey said.
If Clinton wins the nomination, Rendell said he would support her having Obama as a running mate. "With the caveat that I don't speak for the campaign, I think that would be a great ticket," he said.
Meantime, Democrat Barack Obama, who often argues that John McCain is the same as President Bush, suggested Sunday the Republican presidential candidate would be better for the country than Bush has been.
Speaking in central Pennsylvania, Obama said: "You have a real choice in this election. Either Democrat would be better than John McCain." And then he added: "And all three of us would be better than George Bush."
Democratic rival Hillary Rodham Clinton was quick to pounce. Speaking in Johnstown, Clinton said: "We need a nominee who will take on John McCain, not cheer on John McCain."
Earlier, Obama renewed his criticism that McCain offers the same "failed" policies of the Bush administration on everything from Iraq to the economy.
