What are the chances of holmes goin back to the steelers?

I'm not sure if his contract is up this year or next year but what are the chances of him goin back or them taking him back I know the steelers have mike wallace hines ward antwana randle el emmanuel sanders and antonio brown but ward is bound to retire soon and chances are holmes won't stay and I know the new cba hasn't been reached yet but that aside what are the chance?