Maybe it was to stick it to Brady and Kraft for the Jimmy trade.
Passive aggressive move.
Of course people will laugh this off and ridicule to no end, but only two possibilities exist either this or it was for disciplinary reasons. Since Belichick stated it wasn't the latter well we're left to surmise....
The truth has to be the former and it will eventually come out. Butler probably used his sickness to tweak Bill and Bill is not one to be f'ed with.
Make no mistake - Bill's adherence to principle cost him and Brady another Super Bowl.