#3 Olivier Giroud
Few transfers by the Blues' have made sense since Mike Emenalo quit as sporting director in November 2017.
Yet even in this sea of mediocrity, the Olivier Giroud signing stands out as a spectacularly bad one. A striker who was finding it difficult to get goals at Arsenal was deemed to be good enough for the Blues.
Since his arrival in January last year, it has been a tale of struggle for the Frenchman. While players like Hazard have enjoyed playing with him due to his talent as a target man, his goal tally in a blue shirt has been horrible to watch.
10 goals in 44 matches tell the story of a backup striker who does not have what it takes to be a leading man. Alongside Alvaro Morata, Giroud's goal shyness has badly let the team down this season.
Next summer will be a good time for Chelsea to admit that the £18m signing has not worked and move him on.