List their accomplishments, teams, etc. And then note that significant evidence exists that they used performance-enhancing drugs late in their careers. I don't have the answer, but I do know that P.E.D. users are absolutely already in. I don't like Bagwell and Piazza and Ortiz having plaques but Bonds and Clemens not.
I'm not wild about Kent, simply because his best seasons coincided with Bonds behind him in the lineup giving him way better pitches to hit.
Agree with you on Mattingly.