So Rafa will get #1 back until Monte Carlo in a few weeks, and then he pretty much has to equal last year's clay performance or he'll lose #1 again, as he's only +100 points. He's got 4680 clay points to defend: 1000 at Monte Carlo, 500 at Barcelona, 1000 at Madrid, 180 at Rome, and 2000 at Roland Garros.
I suppose his only saving grace is that he could make up some points at Rome if need be, but that's not a lot of margin for error. That said, he could gain it back again if Roger doesn't win Wimbledon, and then lose it again at USO...so the baton could be passed back and forth all year.