#2 Yaya Toure - Olympiacos
Toure is widely regarded as one of the most versatile midfielders of the modern era, as his ability to play both as a defensive and a central midfielder has earned him some of the most important titles both with Barcelona and Manchester City. His leadership qualities and tactical vision have earned him comparisons with the likes of Claude Makelele and Frank Rijkaard, legends in their own right.
While Patrick Viera was the first choice defensive midfielder for Arsenal back in 2003, Toure was brought in as a backup and already had an agreement with the Gunners. However, due to documentation errors, Toure was denied a work permit to the United Kingdom and was sent to the backwaters of football in Ukraine. Unfortunate enough for Arsene Wenger, he later went on to become a star player for Barcelona and Manchester City. Had he stayed with the Gunners, Wenger wouldn't have drowned in regret.