The Texans have finally exercised the $8 million option that extends quarterback David Carr's contract through the 2008 season, a person close to the team said today. An announcement is expected Friday. Also, the Texans are expected to hire former Green Bay coach Mike Sherman as assistant head coach/offensive line, although the move may not become official before next week. Sherman has been on a family vacation and still must work out a contract, but he?s expected to report for work Monday. The decision to extend Carr?s contract has nothing to do with the top pick in the draft. The Texans still haven?t decided if they?ll select University of Texas quarterback Vince Young or Southern California running back Reggie Bush.