While he still has some work to do, Joe Posnanski, of SI.com, feels that Rafael Nadal has a good chance to go down as the best to ever play professional tennis.

Rafael Nadal has won 10 Grand Slam titles

Nadal is certainly on pace to be viewed as the best of all-time. He's won 10 Grand Slam titles, and he's only 25-years old.

Nadal also looks like he's only getting better, winning three Grand Slams in 2010, and one already, this year.

If he stays healthy, and avoids burnout, then Nadal has a good shot to eclipse Roger Federer's 16 Gand Slam titles, and if he does that, he has an argument to be considered the best of all-time.