The reason according to Carwin on his official website: Mono, and supposedly Brock has a bad case of it.
Guys my manager Jason Genet just told me that UFC 108 is not happening. Brock has Mono and what the UFC has told me is that I have earned the title shoot but I have to wait for the title holder.
According to Google Health:
Mononucleosis, or mono, is often spread by saliva and close contact. It is known as “the kissing disease,” and occurs most often in those age 15 to 17. However, the infection may develop at any age.
The fever usually drops in 10 days, and swollen lymph glands and spleen heal in 4 weeks. Fatigue usually goes away within a few weeks, but may linger for 2 to 3 months.
No official word is currently available as to the status of the UFC’s heavyweight championship or Lesnar’s current condition.
Stay tuned to 5 Oz. as we continue to keep you up to date on this anticipated heavyweight showdown.