Looks as though popular lightweight fighter Clay ‘The Carpenter’ Guida’s absence from UFC 2009 Undisputed was because of his long hair.
During development, the hair on his character caused clipping and collision detection issues making him unplayable, so he was taken out of it.
According to 5th Round, THQ supposedly offered Guida money to cut his hair so he could be kept in-game, but he refused.
Bit strange, that.
Clipping issues were also an issue with left-handed fighters like Rich Franklin, and instead of the developers asking the fighter to switch styles, they were just given a right-hand stance in the game.