If you watch the press conference somebody asks why Darby was benched and Rex's immediate response is, "why do you think?" He then pauses for a moment and comes up with the "Darby was sick" thing.
I'm not sure what to think here. It might just be Rex protecting a player to the media or perhaps he wasn't quite himself but when his immediate response is "why do you think?" it makes you wonder if it was because of an "illness."