Alex McLeish, who remains hopeful of signing Robbie Keane from Tottenham, had discussed a £1.25m transfer but has been alerted by Boca's willingness to accept a £200,000 loan deal.
Birmingham and Blackpool have also watched Dundee United goalkeeper Dusan Pernis.
Blue is the colour: Pablo Mouche is being offered a loan route of Boca Juniors
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Explore more:People: Robbie Keane, Alex McLeish Places: Birmingham