I think Santorum will pull it out. Also, are you suggesting Spector's health will force him to resign? I disagree with Spector on many issues, but I do hope he recovers and can serve out his term which ends in 2010.
I don't think Santorum will win, IIRC, he polling below %50, which is death for an incumbent. As for Spector, I thought he was in pretty bad shape.