#3 Alexandre Pato
For someone who evoked comparisons with the legendary Pele, former Chelsea player Alexandre Pato has had a largely underwhelming career despite making a promising start at AC Milan.
Injuries and subsequent loss of form meant that Milan jettisoned the young Brazilian striker. Pato was never the same player again as he struggled to score goals with any kind of regularity.
While with Corinthians, Pato arrived for a short loan spell at Chelsea in 2016. However, the move turned out to be an unmitigated disaster, as the Brazilian appeared short of fitness and sharpness in front of goal. When he was fit, Pato struggled to deal with the physicality of the Premier League and left Chelsea after playing only two games.
It is, however, worth noting that like with Milan, Brazil and Corinthians, Pato also scored on his Chelsea debut, but that was as good as it got for the player at Stamford Bridge.
Incredibly, Pato is only 31 and still has time on his side to have a last hurrah with a top European club, but that looks very unlikely to happen.
#2 Ricardo Quaresma
For a player who played at Porto, Inter Milan and Barcelona, Ricardo Quaresma had a forgettable stint at Chelsea. It was as if Quaresma never turned up for the Stamford Bridge club at all.
After a forgettable 2007-08 campaign at Inter Milan, a loan move to Chelsea could have rejuvenated the Portuguese winger's career. However, it would not be an understatement to say that Quaresma was a massive disappointment at Chelsea.
The player appeared in only five games for the club all season before he rejoined his parent club, Inter.
Inconsistency and perhaps a lack of temperament blighted the career of Quaresma, who failed to do justice to his mercurial ability on the ball. The 37-year-old, who is long past his prime, now plies his trade at Vittoria Guimaraes, whom he joined earlier this year.
#1 Radamel Falcao
Radamel Falcao was nicknamed 'El Tigre' for his exploits in the Europa League, but the striker had a miserable stint in the Premier League, first with Manchester United and then with Chelsea.
Radamel Falcao joined Chelsea on loan in 2015 after a disappointing spell at Manchester United. However, more disappointment was in store for the Colombian.
Persistent injuries meant that Falcao appeared only five times for Chelsea, with his lone goal for the club coming in a 1-2 Premier League loss to Crystal Palace.
Falcao returned to Monaco the next season and regained his scoring touch but has never been the same player he once was. The 34-year-old striker presently plays for Turkish club, Galatasaray.