Paulo Filho (Pictures) will not defend his WEC middleweight crown against Chael Sonnen (Pictures) on March 26, his manager, Jorge Guimaraes, told Sherdog.com.

"We tried our best with Filho, but it didn't work and he'll not fight in the WEC," Guimaraes said. "He tried with all his effort to accomplish the title defense, but he realized he couldn't do it due to chemical dependence and depression. He knew this kind of stuff does not have a link with the sport, and I'm happy he had a conscience and looked for help."

Filho had disappeared for two days, causing immense concern for his teammates and Guimaraes. He ended up checking himself into a rehabilitation clinic in Niteroi, Brazil.

Guimaraes couldn't say for certain how long Filho will stay under treatment, but he suggested the fighter will stay at the clinic until he is 100 percent. Filho is feeling better, Guimares said, after 48 hours of treatment. Guimaraes declined comment on the root of Filho's chemical dependence.

"The WEC staff was superb with us," the manager added. "They understood the situation, and Filho will return and defend his belt in June. Filho also realized who his real friends are, and he took this lesson seriously. He'll come back victorious from this tough moment and he will be supported, as mentioned, by his real friends."

"We fully support Paulo in this difficult time and our thoughts are with him as he goes through recovery, Peter Dropick, WEC Vice President, said through a statement on the promotion's Web site.