Unlike Willie Parker who the Rams kicked the tires on as a potential backup for Steven Jackson, McKie does not fit that role. He's a fullback, a blocker, and we all know where those guys fit when Mike Martz is at the helm.
The Rams have FB Mike Karney, who signed a three-year contract last year as a free agent. An excellent blocker, Karney does have a bit of an injury history, missing two games last year and four the year before. Given that style of play, it's of little wonder. I wonder if the Rams are concerned about Karney's health?