First, Anthony Johnson had to withdraw from UFC on Versus 4 because of a reported shoulder injury. He was slated to face Nate Marquardt in the main event and Marquardt's debut at welterweight. Now Rick Story, who just beat Thiago Alves at UFC 130, will step in.
Cub Swanson also had to pull out of his UFC 132 bout with Erik Koch because, according to his Twitter, he broke his face. He even tweeted a picture of the broken face. The UFC is still searching for an opponent for Koch.
Notice that it is now June, and Zuffa's new insurance policy is in effect. Johnson and Swanson should both be covered as they recover from their injuries, and the fights won't be hampered by fighters who aren't Octagon-ready. If you were looking for a tangible benefit of the insurance policy for fighters, this is it.