9. Jaap Stam (Netherlands)
A defensive rock is a key element of any football team, and in 1998, Sir Alex Ferguson was seemingly lacking in one, having been left with the trio of Ronny Johnsen, Henning Berg and David May as his centre back options following the departures of Steve Bruce and Gary Pallister, his preferred pairing from the early 1990s. Though the Norwegian pair were reliable, United were in need of a strong and dominant force at the back. Step forward Jaap Stam, fresh from a fourth-place finish at the World Cup with Holland, who became the most expensive defender in the world at the time of his acquisition, with Sir Alex paying £10.75 million pounds to PSV Eindhoven to secure his services. His first season at the club was a historic one, despite eyebrows being raised at his mistakes in his debut game, the Charity Shield against Arsenal. The team went on the win the treble, with the Dutchman making fifty appearances at the back, scoring a solitary goal in a victory over Leicester City in the process. Premier League success was replicated in the next two years as United equalled their own record of three successive titles, but Stam, despite continuing to be a wall at the back when not injured, was surprisingly sold to Italian side Lazio in 2001. It later transpired that the sale was due to negative comments that the Dutchman had made about Sir Alex and the team in his autobiography, but the manager came to regret his decision as United surrendered their crown to Arsenal, with aging Frenchman Laurent Blanc proving to be a less than adequate defensive replacement. In total, Stam made 80 competitive league appearances for the club, and returned in 2008 in a scouting capacity, charged with finding young talent in South America.