If a backup RB like TJ Duckett is worth a 3rd and a 4th, a backup and part time starting LB like Scott Shanle might be a 4th to a team desperate for them. Lenny Pasquerreli didn't get to where he is by randomly pulling out information from his large behind that can easily be verified and discredited elsewhere. And from the tone of David Archer it sounded like he was just assuming what Dallas got in the trade, not actually verifying it.
Shanle has become a whipping boy and joke on this messageboard, much of it due to some interpersonal reasons between past posters, but that doesn't mean zilch in regards to his value around the league.