MMAJunkie.com has the story:
UFC heavyweight Heath Herring (28-14 MMA, 2-3 UFC) has been forced out of next month's UFC 99 fight with Cain Velasquez (5-0 MMA, 3-0 UFC) due to an injury.
That's the word from UFC officials, who stated a replacement will be named on Wednesday.
UFC 99 takes place June 13 at the Lanxess Arena in Colgone, Germany. The Herring vs. Velasquez bout had been slated as the night's co-headliner to a main event of Rich Franklin vs. Wanderlei Silva.
According to MMA FanHouse, which first broke the news earlier today, Herring was forced off the card not due to an injury but instead due to an illness that's kept him out of training for the past few weeks.