The Australia international has come off contract at his Dutch club, though Heracles Almelo are insisting he fulfil an extra one-year option in the agreement.
Club director Nico-Jan Hoogma has confirmed they've requested Davidson meet his obligations, though the World Cup veteran is insisting he's a free agent.
West Brom, meanwhile, are monitoring developments.
Davidson is the son of former Nottingham Forest and Australia fullback Alan Davidson.
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