Well, based on recent play, the logical move would be Cassel. However, the Pitt defense is awfully stingy and could give Cassel and co. a lot of issues.
Plax will be out most likely, although Eli's put up two good games without him. If Jacobs is back, I'd take my chances with Cassell. If not I think Eli will be expected to carry the offense again, like last week.
I just think you are better off avoiding Pittsburgh's defense. Eli threw for more scores without Jacobs and there haven't been any games where the offense has been completely shut down. Basically you get the #1 offense and avoid the best defense I've seen. The Giants look due for an off game, but I still think Eli is the smarter play.