Once Teagarden showed up to grab some quality HGH from Sly, AJ's defense basically became air-tight. Publishing Sly's other statements on his alleged clients--given his knowledge of the chemicals and access to them and athletes--was not reckless, and there is certainly no positive evidence to suggest that any of this is false, let alone that AJ published it knowing so.
Ideally for these athletes, assuming innocence, Sly would be the guy to sue. However, Sly had no idea these statements would be made public and when they did he disavowed his statements, so they are basically screwed from that angle, too, since they can't meet the publication element against Sly. Brady has a better case against the NFL than anyone does here against AJ, provided he can establish that the NFL gave Mort the info, which probably can't be proven in court unfortunately. I would say the odds of giving up his source willingly on that are...quite low.
If any of these guys are actually innocent, you do have to feel bad for them. I would bet against any of them actually being innocent, but I have been wrong once or twice before.
Edit - Hmm, not so sure on the publication element from Sly's perspective, actually. "Publication" in standard defamation cases can occur when a false statement is communicated to even one person. I don't know if public figure cases raises the standard from one person to a more broad audience or not. My guess would be yes, but I can't find anything quickly to confirm that. He also did quickly retract the statement, so my guess is he'd still be ok.