I agree with drummer, you need to DFA them. Clears the roster spot and maybe you get lucky and someone claims them. If not, may as well stash them in the minors and use them if injuries force you to. I'm guessing there is a season or two left before the option year, if that's the case, that is most likely why you can't release them.
You may find someone to take one of these players on if you add a prospect of value. It's an expensive way to do it but if you're not willing to wait, it's the only way it will happen.