Ferentz and DJK never got along, but I think that was due to differences in attitude. I sincerely doubt Ferentz knew about this drug problem. I think there would have been players on the team who would have known, but as anybody who's been on a team knows...you tend not to snitch on your teammates. Especially if they're the best player on the team.
Looks like DJK's neighbors didn't have any idea about the drugs thing. They did say that parties on Saturday nights after home games got loud, but other than that, they said he was a quiet kid.
The cops had been tracking his roommate for a while, and the warrant was to go after him. DJK wasn't the target of the investigation...at least at first.