Clutts is bigger, older & slower, but he's important to our ST's. That probably will keep him on our roster. Unga is younger and faster than Clutts (about as fast as Bush) and Unga is very quick/agile for a big back. Unga is clearly a better RB, but Clutts is probably a lock to make the team. I don't think they'll keep Unga. But he'll get picked up by another NFL team. He has the talent. We just don't have room for him on our roster.
At least that's my guess. The only thing that might change this, is if Bell continues to fumble. Then they'll dump him.