BB benched him. He also benched Seymour back when he played here and also benched Welker. I'm sure he's benched other good players for disciplinary reasons. But when he's on the field, he's pretty good. You have Reed and Polamalu as the best safeties in the league. After them, Merriweather is as good or better than anyone else. Why would we get rid of a guy like that?
Chung, as good as he is in run support, is awful covering receivers. Hell, Sanders is better than him in coverage and I think he's awful too.
Unless we have a good replacement for Merriweather, which we don't at the moment, I don't see how getting rid of him is good for our team. Our pass defense is already a joke.