Michael Clarke Duncan will guest star on 'Bones' in an episode that will serve as a backdoor pilot for a spinoff.

Duncan will play Leo, described as a cowboy philosopher. The proposed spinoff is based on 'The Locator' books by Richard Greener. The novels follow Walter Sherman, a former member of the military police. According to TVLine, the role of Walter has not yet been cast. Duncan's Leo is partners with the main character.

This could be the first regular TV gig for 'The Green Mile' star.

In other TV news ...

• Loretta Devine is returning to 'Grey's Anatomy.' The 'Boston Public' veteran is reprising her role of Adele Webber in a mid-February episode. [E! Online]

• In other ABC medical drama casting, Paula Malcolmson will guest on 'Private Practice.' The 'Caprica' star pops up in episode 14 as the wife of a convicted killer. [TV Guide]

• Eric Balfour has been tapped to guest on 'No Ordinary Family.' The '24' star will play Marcus Winnick, a death row inmate for two episodes. Look for him in March. [TV Guide]

• Suzanne Malveaux is leaving her CNN White House correspondent gig. Malveaux will now anchor 'CNN Newsroom.' [Hollywood Reporter]