Schalke striker Klaas-Jan Huntelaar has confirmed he will miss three to four months of action after opting to have an operation on his knee.
The 30-year-old had returned to training following a previous knee injury but suffered a further setback on Monday and revealed his disappointment at the prospect of another lengthy lay-off on Twitter.
"It was difficult, but I have decided to undergo an operation. Regeneration time will last three to four months. It is a difficult but necessary step," the 30-year-old announced via the social media site.
Schalke coach, Jens Keller, had earlier given his thoughts on the plight of the Netherlands international on Thursday and insisted the striker had been given the best possible treatment prior to his original return to action.
He said: "We didn't rush him back before he got injured. Usually an injury like his is fine after eight weeks. He felt good.
"He took part in everything and this setback was an accident. He collided with someone in a bad position. This would still have happened even if it was two weeks later."
The German club sit eighth in the Bundesliga after eight games and continue their campaign with a trip to Eintracht Braunschweig on Saturday.