4. Brad Friedel
Francisco Seco/AP/Press Association ImagesThis may come as a surprise to some, but in 1993, Brad Friedel was actually very close to starting his infamously long and successful professional career at Celtic. Friedel was a bit of a late starter in the professional game at the age of 22, due to playing college football in the US for quite some time, and he was brought in by Liam Brady, Celtic's manager at the time, on trial. For some reason, Brady didn't want him, unlike Nottingham Forest and Newcastle who both tried to sign him but couldn't secure a work permit for him. It is thought that Brady couldn't see him offering any competition to Pat Bonner or Gordon Marshall, and it's no real surprise then that Brady was later proven not to really know what he was doing with Celtic anyway. Shay Given was also at the club with Friedel trying to prove his worth, although he was a Celtic youth player at the time and basically on our books already before we stupidly let him go too. Here you go world, have two of the best young goalkeepers around, you're welcome...