When I say sign Sitton cheap, it's with the idea that if he is worthless, he could just be cut. There's probably a better than even chance, though, that he still has enough that he is better than at least some of the O Linemen currently on the roster. What's the harm in that?
a) he will get the veterans minimum and I believe it will be guaranteed at this point in his career.
b) he takes reps from a younger player that will be better than him by next season.
c) some team will pay him more than that if he isn't completely worthless.