Boxingtalk has learned that the IBF has designated DaVarryl Williamson as the mandatory challenger for Chris Byrd's heavyweight title. Earlier this week the Jersey based organization ordered the two to commence negotiations. However, Wladimir Klitschko has filed an order to show cause in United States District Court in New Jersey seeking to stop the IBF from enforcing this mandatory.  Back in September, Klitschko defeated Williamson by technical decision, but many felt the result was unsatisfying, since Klitschko was knocked down in the bout and didn't seem to eager to continue after he suffered a cut. Initially, Klitschko was rated ahead of Williamson in the IBF ratings, but after Williamson knocked out Derrick Jefferson, he was moved ahead of Klitschko.  The legal team for Klitschko, which includes television personality Max Kellerman serving as an expert witness, has accused the IBF of manipulating the rankings as a favor to Don King, who promotes both Byrd and Williamson. The IBF has not backed down, however, and in its response, the New Jersey-based sanctioning body argues that the WBA and WBC also rate Williamson ahead of Klitschko. Boxingtalk rates Klitschko and Williamson at # 11 and 12 respectively, which includes the four recognized world title holders. REMEMBER WHERE YOU HEARD IT FIRST! (11:15 AM EST) More to come.