5) Ibrahim Afellay
When he joined Barcelona in 2011 Afellay looked destined for great things. He was injured during pre-season with the La Liga club however, and after finally making his return he was hit with an ACL injury.
His record saw him pushed out the door on loan to Schalke 04, but his injuries continued with the Bundesliga club and he has never reached the heights that were expected of him.

