Oh. Sorry about that. Check your depth chart and see those linebackers are assigned to the 3-5 roster spots for CBs. If nobody is assigned to them then put the other corners in there. If that doesn't work the only thing I can think of is to pick the play from the playbook and then sub in the corners for that formation. I think once they get subbed in they stay in even if you use your gameplan the rest of the game.
I hope this helps I've never heard of your linebackers playing the nickle and dime CBs so this is the first time I've heard of this problem.