THUNDERVOLLEY
G.O.A.T.
A. The ITF's drug testing system is easily fooled. It is in fact one of the weakest systems ever. This whole business about tennis having a strict testing system is total BULLCRAP made up so that people don't worry about steroids/doping.
B. There is precedence set in the past that shows the ATP/ITF will sweep things under the rug if they feel that it will damage the sport. Good examples are the recent Agassi meth incident, along with the infamous Rusedski case where it somehow got dismissed under bogus circumstances.
C. Nadal has been accused by a newspaper of being on the list of Doctor Fuentes, well known doping doctor. Not just that, Doctor Fuentes himself admits that he has helped tennis players, soccer players, etc. and not just cyclists.
D. The list has never been released as it is being held up in court by Spanish authorities. Hrm, I WONDER WHY? The only thing the Spanish authorities have said on the matter is that "don't worry we are telling the truth *wink* ".
E. As Drakulie stated, Nadal's Wimbledon withdrawal was dubious and can be considered suspicious.
These all tie together and there's an overwhelming amount of evidence to suggest that many top players in fact have the opportunity to dope, and that it is absurdly easy to get away with it. Even if they do, they can just say "Dude, it was an accident" and get away with it, like Agassi did.
....then you are (for all purposes) throwing your collective hands up, and calling it a day. Unless an official outside body can force Spanish authorities, the ATP & ITF to cough up all relevent information on Nadal (assuming the alleged information has not been destroyed at every source), then all one has is suspicion. More substantial smoking guns are required.
OP: Agassi seems to be continuing on his path of image-shaping and damage control. While Sampras was consistent in making his own history, Agassi repeatedly pissed away his career (which the protective ATP, and certain ex-players never commented on) until his 11th hour salvage job, which makes his number of slams earned over a pockmarked period of time far less impressive than that of the career of Sampras, or even others of his generation with not as many, such as Courier (or the slightly older generation of Becker & Edberg).
That said, this appears to be damage control; at any time, a former celebrity's stab at a bio can be beaten to the punch by other publishers around the world with as much information on the former star as the star himself--including damaging information. Since Agassi's drug abuses was not the Riddle of the Ages, he (Agassi) likely realized others were preparing tell-all bios, thus to appear like a humble, repentant little ex-celebrity, he now tries to reduce the shame by revealing the drug abuses before others can. Will this prevent other tell-all books from surfacing? Who knows, but the books (if they exist and are on the schedule for a run) are likely waiting on Agassi's, and what it may reveal..or supress.
Agassi scores no points with this move.