If he Nadal wins FO, and Federer wins Halle and wimby then he will be #1. Ahead of Novak by 80 points.
Very very unlikely to happen. Did people see Fed these last 2 weeks?! He was atrocious. No two ways about it. Says a lot about Del Po that he couldn't beat a Fed playing like this. Goffin, Ungur & Mahut took sets off the guy - think about that.
He wasn't good in Rome either - just had a good draw to the semis - titans like Berlocq, nearly retired JCF and Seppi was a great Masters draw. Looking at his level of play he has not been anywhere close to slam winning form - the biggest worry has been his serve. Is he suddenly going to recover and have enough to beat the likes of Nadal/Djoko/Berdych/Tsonga/Del Po/Murray on grass? The only way I see him winning is by again having a LOT of luck with the draw - with the serve & FH as they were in the semi vs Novak I can't see him beating even Berdych/Tsonga/Del Po, let alone fellow top 4 players.
Frankly no way is he anywhere close to Nadal & Djoko's level right now - they've got to the last 4 slam finals, Nadal the last 5. So if by some miracle he did get to no.1 in the next month it would be quite laughable - no players would actually think he's the best player in the world no matter what the ranking said.