It seems that the UFC 196 main event is doomed as UFC Heavyweight Champion Fabricio Werdum has also pulled out of the show due to injury, as reported by mmafighting.com here
Challenger Cain Velasquez pulled out of the bout yesterday with a back injury and was replaced by top contender Stipe Miocic. But now the Champion has also withdrawn from the fight.
No announcement has been made yet as to what fight will headline the card which takes place in just over a weeks time.