I’m not at all au fait with sporting contracts, but I would have thought a contingent break clause, fairly widely worded, would be pretty standard in a player’s contract at the top of the game, where a competent agent and legal representative were acting on behalf of a player who, by virtue of his standing in the game, had solid bargaining power. I would have thought that would be pretty commonplace at that level, if not universal.
It certainly wouldn’t need to specifically mention the charges to be effective. It would simply need to refer to material disciplinary findings against the club having a significant negative reputational impact, amounting to a repudiatory breach of the agreement. Why make your client a hostage to fortune in circumstances such as those? They would then have the option (rather than be obliged) to terminate the agreement, possibly subject to an agreed transfer fee at that point as provided for in the contract. This would, to some extent, protect the club’s interests, and make them more liable to agree to such a clause.
I think that clause, worded more widely, would also give a level of plausible deniability about specific break clauses relating to the charges, especially if those types of clauses were commonplace.
All guesswork, mind!