Big talk for a man suspended until December for failing his drugs test.
He's just trying to get JDS angry enough to wait for him, and so the fans don't forget about him while he's away.
Its so obvious to me that Overeem is using words to get a title match sooner rather than remaining quiet and waiting till the winner of Cain/JDS. If a fighter falls for trash talk, then by all means, use whatever tools to get the fight.
For the most part, I take trash talk from any fighter with a grain of salt.