Summary: A late-season addition, Schaefering picked up the techniques well and immersed himself into the Cowboys locker room pretty quickly. He had a minimal impact on the team.
Why keep him: You can never have enough defensive tackles, especially when you're moving to a 4-3 scheme that needs defenders to push the pocket. The uncertain futures of Jay Ratliff and Josh Brent due to their arrests means the Cowboys are thin at this position, so Schaefering gets to stay.
Why let him go: The Cowboys didn't seen enough of him and there's nothing wrong with looking at other players, specifically draft picks with more upside.
Best guess: He stays with the team. It can't hurt to have him around getting to know the scheme and maybe becoming a reliable backup.