New Delhi, Oct. 30 -- LAS VEGAS - Sean Brady said he could not walk by the end of a training day that had started normally. The swollen knee that sent him to hospital has now cost him his fight against Gabriel Bonfim and changed the main event of UFC Vegas 124 with nine days left before the card.

Brady withdrew from the November 7 welterweight bout at Meta Apex after an infection and recurring fluid buildup in his knee. He said he spent three days in hospital receiving treatment and that tests identified staph bacteria. His account gives a specific explanation for a withdrawal initially reported simply as an injury.

UFC has a replacement headliner, but not a replacement opponent for Bonfim. Waldo Cortes-Acosta and Johnny Walker will mee...