That's what my 2nd statement meant I think they are not saying he tested negative on later tests, they're saying after testing positive for the diuretic, they tested him for other substances but found no traces of anything else BUT the diuretic.
I don't have a horse in this race but anybody who knows me knows I'm damn near obsessed with cheating and this sort of thing, spent years here and elsewhere arguing Lance was cheating and would eventually be caught. I think it came from growing up an A's fan and then seeing Canseco and McGwire and hearing all the rumors years before they got caught.
Drug testing is EXTREMELY scientific, it's not BS and when you consider the amount of tests they do, the instances of false positives are actually quite low. Players are trying to get an edge and it's remarkable what they will do to try and beat the system, taking horse steroids and adderall and all sorts of other stuff. If I had to guess I would say Ayton smoked some pot, then decided uh oh I might get tested so he got a diuretic to try and flush his system out and tested positive for that. It's almost unheard of these days for an athlete to test positive and say yeah I did it.
I think 25 games is excessive based on the information we have but I suspect it either means he'd already tested positive before and we didn't know it, or he was suspended because they saw the diuretic use as evidence he was taking something and tried to hide it so they gave him a higher suspension. I would hope it's reduced to more like 10 games or less dependent on what else comes out.