The Daily Express says Campbell has been told he must agree to a five-year â€śgagging orderâ€ť by Notts County before they let him continue his career.
County are refusing to release Campbellâ€™s registration and he is calling on playersâ€™ union chief Gordon Taylor to intervene on his behalf.
Campbell wants to go public on certain aspects of his time at County, which ended after only one game â€“ a defeat at Morecambe. County want him to keep quiet before a â€śstatement of departureâ€ť is agreed.
Taylor said: â€śClearly, Sol needs to express the real reasons behind his departure, and will not agree to a gagging order. Instead, we are trying to agree a form of words, a statement both sides are prepared to accept.â€ť