10. Klaas-Jan HuntelaarSchalke 04 striker Klass-Jan Huntelaar is a player many teams have looked to sign down the years, and a player who has played for some of the biggest clubs in the world. Hes regarded as one of the best strikers in Europe, and the 31-year-old could be available for free this summer with his deal set to run out at the end of the current campaign. Huntelaar, a Netherlands international, has played more than 400 games in his career, scoring over 270 goals for the likes of PSV Eindhoven, De Graafschap, AGOVV, Heerenveen, Ajax, Real Madrid, AC Milan and Schalke. Hes bagged 35 goals in 65 games for the Oranje, and has a long list of personal accolades for his goalscoring antics with club and country. The 31-year-old would strengthen the majority of European sides, and Schalke could well struggle to convince him to sign a new deal if other clubs show an interest in the coming months and offer him the chance of a final gigantic contract before he retires or steps down a level.