Former Schalke 04 assistant coach Sven Hübscher has admitted that they could not control Boateng's injury problems during the latter stages of his spell at the club.

Kevin-Prince Boateng had a successful stint with the club, scoring six goals in 45 appearances for them.

Sven also added that the 33 year old wasn't fazed by the opponents they faced.

"These were not human reasons, we simply could not get his susceptibility to injury under control. He was no longer as efficient as we were and he would have wished for it, because even under Roberto Di Matteo, whom he always addressed as a Mister, he was an important personality," he told Goal and Spox.

"Through his self-confidence. He didn't care whether we played against Leverkusen or Bayern Munich. He didn't give a shit. He simply had this self-image, which everyone has to orientate on him. This helped our entire team at this point. And of course, he could also kick very well.