Here are the current standings: 1. Nadal - 21 2. Federer - 20 3. Djokovic - 12 4. Murray - 8 Here are my predictions: Nadal: He's currently having some injury issues, but I think he'll get back on tour and even when he's not at his best, he's still the favorite for any clay tournament. He should be able to win one or two clay Masters for the next few years. I think he'll win five more and end his career with 26 Masters titles. Federer: By far the oldest of the bunch, but he's already won two this year, and I think he'll be a contender for hard court Masters events for at least another two or three years (even if his overall consistency in them begins to drop). I think he'll win four more and finish his career with 24 Masters titles. Djokovic: He probably won't have another 2011, but he's still good enough to win two or three a year while he's still in his prime. Additionally, he can win clay Masters events with or without Nadal in his way. I think he'll end his career with 19 Masters titles. Murray: He's won two titles per year for the last four years, but only has three more opportunities to match that this year. He might just be able to sneak a clay Masters as Nadal gets older, but I think it's very likely he finishes with only hard court titles. I think he'll end his career with 14 Masters titles.