The Dutchman missed the start of the season after undergoing surgery which was designed to clear up the problem for good, but he says that the injury is continuing to bother him.

"I feel pain almost every day," he said. "It is the most frustrating injury of my career, and I have had a few."

The 28-year-old recently started three games on the bench for Bayern after failing to rediscover his best form after injury. His performance against Schalke last weekend caught the eye, but he says he is still not back to his best yet.

"I can just manage to be fit for games with adrenaline and all that, but I cannot truly say that I am back to 100% again," he told Dutch television channel NOS.

"Things are going in the right direction. All I need now is to play games to get back into a rhythm."