I'm not sure what you mean about Agassi being seventh seed...it depends who he replaces and when he replaces them, doesn't it?
If someone withdraws before the draw (assuming that takes place next Wednesday?), then he will be eighth seed if he replaces Gaudio and seventh otherwise. If a player pulls out after the draw has been made, Agassi will just replace him directly. Either way, he could still face Roddick in the RR. Or have I missed something?