For Sammy it was clear that this team was not going to pay him the $15M per year contract that he would demand for the production from him. If he were retained for this year, he would have walked. We have a 2nd round pick for him that could turn into a player for the next four years. The balance was heavily favored towards the getting the pick.
Dareus was the easy one...He had conditioning problems and was penciled as the Starter here. He couldn't break into the starting line up. How do you pay him $100M to be backup. The JAX were leaking against the run and were desperate and had the cash...so they made the deal. They are not on the hook for anything for Dareus and could cut him this offseason...For them the risk to rewards was pretty high and hence they chose the trade. If Dareus could have a great training camp and push to be the starter, then it may come back to impact them on their salary cap.
The case Darby was the hard one to understand. There must have been something going on inside that build that we are not privy.