8.
Martin Rickett/PA WireBefore the German went on to enjoy a glittering career with the likes of Aston Villa, West Ham, Stuttgart and Everton, Thomas Hitzlsperger was released by Bayern Munich at the age of 18 in the year 2000. What many don't know is that Hitzlsperger actually had a two week trial with Celtic immediately afterwards, and why not? No one should ever ignore young talent coming out of a team like Bayern, and it's typical of Celtic to be in there first to take a look with their excellent scouts. Unfortunately, it's also typical of Celtic to take players in on trial when they should have just taken the gamble, this being the case. No deal was ever negotiated, and young Thomas joined Aston Villa very soon after the trial, and that was his career set. It's always very disappointing to hear that your club could have signed a top class player when they were young and affordable, and it's easy to imagine how much excitement he would have brought the fans with his performances. Never mind, It's not like Celtic needed him that season, as they won the treble.