Redskins running back Clinton Portis has endorsed Mike Shanahan as a potential replacement for coach Jim Zorn. Portis said Wednesday that "if they have a change, then of course they would get the thumbs-up vote for me for Coach Shanahan." "If Coach Zorn is done, I would think that's a great direction to go in, if you can get Coach Shanahan," Portis said during his weekly appearance on "The John Thompson Show" on ESPN 980. "But I don't know if Coach Zorn will be gone." Portis hasn't played since suffering a concussion Nov. 8 and was placed on the season-ending injured reserve list on Dec. 8. He played under Shanahan in Denver.