Robinson broke his arm from defending a kick during a recent sparring session.
"First off I want to say sorry to Anthony because I know he had trained his butt off for this fight," Robinson said. "I had the best training camp of my life for this fight. Training with Trevor Wittman and the team out of T'sko has turned me into a different fighter. I have never had this kind of training or a team of guys that have helped me like this before. Royce Gracie even flew in for a couple of days to help me. Ultimately I am very disappointed and heartbroken that I am unable to fight April 11th in my hometown."
Anthony Morrison will be left without an opponent and "The Ultimate Fighter 3" alum Mike Nickels will now headline the fight against James Funny in a light-heavyweight bout.