Roger's chances to take back the top spot in the ATP Rankings are slim but possible after the Australian Open. Murray can't get the 2nd place. Nadal will lose the 4th place.
Here we are at the first slam of the season and we are already doing some calculations about the would-be rankings after the 2013 Australian Open.
Federer world no.1?
This year's question is if Federer can regain top spot in the rankings. The Swiss Maestro can make it only if he wins and Djokovic doesn't reach the final 4.
Djokovic has 12.920 points. Federer has 10.265pts. Taking out last year's Australian Open points, Djokovic will start from 10.920pts (12.920 - 2.000pts), Federer from 9.545pts (10.265pts - 720pts). So Federer will be 1.375pts away from Nole.
The only chances for the Maestro to be back as world no.1 is winning the Austrailian Open (2000pts) and hoping that Nole does not reach the semifinals.
If Federer wins and Novak reaches the quarters, Roger will have 11.545pts vs. Novak's 11.280pts.
It is quite difficult that Nole loses before the semis unless Querrey or Berdych can upset him (here the draw analysis)
Murray world no.3
Andy doesn't have any opportunity to become world no.2 after the Australian Open.
In fact, taking out last year's Australian Open points (720pts as Murray lost his semis against Djokovic) Andy will start from 7280pts that is too far from Roger's 9.545pts (more than 2000pts)
Nadal to lose world no.4 to Ferrer
Rafa will lose his 4th spot as taking out his points from last year's Australian Open he will have 5.490pts (6690pts - 1200pts). David Ferrer will start from 6.145pts (6505pts - 360pts).