In 2005, Chelsea fought off stiff competition from Manchester United to pay £24.4 million for a Ghanaian central midfield with a fine reputation after some outstanding performances for Lyon - but few could have predicted just how crucial Essien would become for the Blues.

He moved to France in 2001, joining Bastia from Liberty Professionals, and reached the French Cup final in his debut season before joining Lyon where two Championship medals and the 2004-05 French Players' Player of the Year award followed.

A commanding figure in the middle of the park, Essien is a fearsome tackler, but is also able to drive the team forward with his powerful runs: creating goals, as well as netting some incredible strikes of his own. He has also shown great versatility, playing on the right-hand side of both defence and midfield to great aplomb - though you feel it is in midfield where he is most at home.

Essien tasted success early in his career as he picked up a gold medal with Ghana at the African Under-17 Championships, a bronze medal at World Under-17 Championships and silver at the World Youth Championships. The midfielder made his full debut for Ghana at the 2002 African Nations Cup and helped the Black Stars reach the World Cup for the first ever time in 2006. Essien ruptured his cruciate ligament in a World Cup qualifier in September 2008, but after returning in March he has helped secure Ghana's place at the 2010 finals.

But Essien has struggled to recover from that knee injury and was injured again at the 2010 African Nations Cup final, an injury which cost him a place at the World Cup finals on African soil.

Essien picked up a second Premier League title in 2009-10, but injury restricted him to just 13 starts in the league. With just 25 Premier League appearances in two seasons, the affect of his knee problem on his career is clear.

Strengths: His power, drive and relentless work-rate. He also possesses an incredible shot from distance - goals against Arsenal in the Premier League and the 2009 Champions League semi-final against Barcelona are proof of that.

Weaknesses: Heading - Essien was famously beaten in the air by Cristiano Ronaldo when he scored Manchester United's goal in the 2008 Champions league final.

Career High: In 2006, he won the Premier League title with Chelsea and played for Ghana in their inaugural World Cup in Germany, as well as being nominated for the FIFA World Player of the Year award.

Career Low: Two years spent fighting knee problems which forced him to miss the African Nations Cup and the World Cup in Africa in 2010.

Style: Combative box-to-box midfielder who likes to be involved with play at all times, whether in defence or attack.

Quotes: "It was an important return, he came back very well and played very well. He is a fantastic player, we missed him last season and we hope he can do the best for this season," Chelsea boss Carlo Ancelotti after Essien's goal-scoring return from injury against Crystal Palace in a pre-season friendly, July 2010.

Trivia: Essien's nickname is "The Bison" because of his powerful physical presence.