6: Scott Parker
Signed by boss Claudio Ranieri in January 2004 for £10m after a protracted and much-publicised transfer wrangle between the Blues and London rivals Charlton Athletic, Chelsea fans were then left wondering what all the fuss was about in the first place.
And following the arrival of Jose Mourinho at Stamford Bridge to replace Ranieri that summer, the English defensive midfield player then spent the majority of the next campaign warming the substitutes’ bench, before being sold to Newcastle United for just £6.5m in July 2005.
5: Alexei Smertin
Another player who arrived at Chelsea in the immediate aftermath of Russian billionaire Roman Abramovich buying the Blues in the summer of 2003, with the holding midfield player being bought from Ligue 1 outfit Bordeaux that August for £3.45m.
However, the Russia international was immediately sent to fellow Premier League side Portsmouth on a season-long loan, and then again to Charlton for the entire 2005-06 campaign, before Dynamo Moscow bought him in 2006 after having played in only 16 Premier League matches for the club.