In defense of Fish :
He did have to deal with some medical issues, but seems to be on his way back.
Don't think he'll stay at #24...
Also, played a bit with the numbers:
Even if Fed has a poor showing at the USO, and Novak defends the title, Fed will remain No.1..
Worst case scenario:
Fed looses 1st round, looses the 720 points from last year's semifinal appearance : 12165-720 = 11445 pts.
Novak defends title and points, stays at 11270.
After the USO, it becomes a little more intersting :
Neither Novak nor Roger played Shanghai, so no points to defend there...
Question is, will they skip it, or play it, to pick up some more points ?
My guess is, at least Roger will skip it, in order to be rested for Paris and London, where he has 1000, and 1500 points to defend...
Novak has only 180 points to defend from Paris, so he will have a chance to narrow the gap there.