Dareus isn't mentioned as a trade candidate because that would result in $27M in dead money, which would INCREASE his 2016 cap hit by $12.5M, which the Bills don't have. So there's that. I don't disagree about him being a poor fit in Rex's defense though, but that's on Rex not Dareus. Mario wasn't the only expensive player that doesn't fit Rex's defense, he was just the easiest to part ways with. Guys like Dareus and Hughes aren't going anywhere anytime soon.