Those claiming all top level tennis players have doped at some point in their careers - are you including Nadal in that population?
I don't really want to get bogged down in specific allegations against specific players because:
(a) it will get fantards in here completely missing the point and defending their hero, and
(b) it will give the mods an excuse to delete/close/bury this discussion for the 100,000th time.
The real problem is the system. In most sports, a player taking time out for injury is a player taking time out for injury. In tennis, because of the lack of transparency and lack of out-of-competition testing, when someone takes time off for injury there are always whispers. They might be genuinely injured. Or they might be serving a silent ban for missing dope tests. Or they might be using a minor injury as an excuse to get juiced and avoid in-competition tests. Nobody knows.
People are whispering about Nadal's current layoff, and it's not because of anything he's done - it's because the system is so weak that nobody has any faith in it, so they're willing to think the worst of any potentially-suspicious circumstances.