if you have this problem during the offseason all you will need to do is offer them a contract. This will then make the cpu start bidding on them so even if you don't want the player you can refuse if he does want to sign with you. This is what people are starting to do with atleast some of the top QBs so teams will sign them and won't go all draft crazy with 16-26 QBs taken in the first round.
Now if this player gets cut before the preseason then you will probably haveto wait until someone needs to fill a hole or until next offseason. Just pretent like the player had some off the field issues and was cut.