Kim Kallstrom
The Swedish international had been an excellent player at the highest level, particularly during his six-year stint at Lyon, but with Arsene Wenger needing to reinforce a midfield ravaged by injury, he decided to snap up the player on loan from Spartak Moscow in 2014.
However, Kallstrom only played four times with it being later revealed he had arrived at the club with a fractured vertebrae. Despite the back problem, the Gunners still sanctioned the transfer despite knowing he wouldn’t be available for two months.