Sen. John McCainJohn Sidney McCainBiden eyeing Cindy McCain for UK ambassador position: report The Memo: GOP mulls its future after Trump Juan Williams: Obama's dire warnings about right-wing media MORE (R-Ariz.) has personally recruited former Homeland Security Sec. Tom Ridge to run for Senate in Pennsylvania next year.

"Yeah, I'd like for Tom to be in the primary," McCain said Wednesday on the conservative Hugh Hewitt's radio talk show. "I had a conversation with him, and I've had several conversations with him over the years."

Reports have swirled that Republicans, nervous about conservative candidate Pat Toomey's chances in the general election, have gone fishing for a new candidate. McCain, the party's more prominent face during the 2008 presidential election, is the latest official to acknowledge an implicit worry that Toomey cannot win.

"There may be some specific areas that we are in disagreement, but he's a Vietnam war veteran, he won in a Congressional district that was Democrat, he did a very good job as governor of the state, and I think he can win," McCain said. "But I also understand that there are other candidates in the race as well. I just happen to be very close friends with Tom Ridge."

The winner of the Republican primary will face off against the winner of a possible primary between Sen. Arlen Specter, Rep. Joe Sestak (D-Pa.), former National Constitution Center CEO Joe Torsella.