Football transfers can be extremely complicated, even when two clubs agree a fee and a player is willing to make a move - as Villa discovered when they made a bid for American goalkeeper Brad Guzan.

A deal was set up in January for Guzan to move to Villa Park from Chivas USA, only for the transaction to be put on hold because the 23-year-old keeper was refused a work permit.

Manager Martin O'Neill refused to give up, though, and nearly eight months later Guzan became a Villa player when the permit was finally granted.

Even then, Guzan was forced to delay the start of his new employment, missing the start of the Premier League campaign because he was with the United States national team at the Olympic Games in China.

Guzan, who learned his trade playing college football in Chicago, played more than 80 games for Chivas in Major League Soccer and was voted the MLS Goalkeeper of the Year in 2007.

He made his international debut against Guatemala in February 2006.