I just don't believe there's any chance Rendell would name Casey to dogcatcher, let alone senator. The Caseys and Rendell do not get along and Ed Rendell is fiercely pro-abortion. Babs Hafer is exactly the sort Fast Eddie would name to replace Specter.
Wasn't Santorum's 2000 opponent also a little more moderate on the abortion issue? It was his lack of support from the pro abort crowd that kept Dems from being too enthusiastic about him, and Santorum was able to win. Maybe if Casey is the nominee that situation will be the same. With Hafer, who seems to love the idea of killing babies, in the running, the Demo primary could get very nasty and divisive. This only helps the incumbent.