Sean Sherk ducks out of UFC104!!!

Sean Sherk has claimed he has an injury and has pulled out of ufc 104,remarkably just hours after he was picked to undergo a random drugs test,Josh Neer has stepped in and will face Gleison Tibau at ufc 104.Now is it a real injury or because he has a somewhat checkered history with drug testing has he decided to pull out before they can test him and then subsequently ban him again...Makes ya wonder.