With Clinton Portis likely missing Sunday's game against the Denver Broncos, the Redskins could have a new running back on the roster in the next few days. What's not as clear: whether Larry Johnson will be that new running back. Johnson was released this morning by the Kansas City Chiefs. If he clears waivers, he'd become an unrestricted free agent and any team would be free to negotiate for his services. There are several reasons the deal could go down. First, Portis' status...