I would suggest something like ... accusé de se défiler de son match / d'esquiver son match en demandant un prix excessif (literally, accused of chickening out / of dodging by asking for too much).
Or, with a different nuance: accusé de se mettre hors jeu / hors compétition à l'avance de son match par ses demandes financières excessives.
As a rule of thumb, these verb + preposition constructions get reversed in French: the meaning conveyed by the preposition in English becomes the verb in French, and the English verb becomes a gerund or some sort of adverbial clause. A classic example is traverser en courant for run across the street.
In the process one must draw from context to make the French verb more specific than the preposition could be. Sometimes this is a bit of an editorial decision, and here the context is actually insufficient to know if the accusation is one of cowardice or of greed / snobbery.