Looks like it was a mistake. From Clayton's injury updates (dated today) on ESPN.com insider:
http://insider.espn.go.com/nfl/insider/columns/story?columnist=clayton_john&id=3092212
"Linebacker Mike Vrabel is questionable with a shoulder injury but he will play. He's coming off the best game of his career. Watson is listed as questionable, but should play."
"Wide receiver Marvin Harrison missed another practice Friday because of his knee injury and may not be able to play. The odds aren't favoring him being out there because the team is concerned that playing him with the knee injury could keep him out for more games. Left tackle Tony Ugoh missed Friday's practice and is also questionable."