Germany goalkeeper Rene Adler was yesterday ruled out of next month's World Cup as he is set to undergo an operation to repair damaged ribs.

"This was the toughest decision of my life," said the 25-year-old Bayer Leverkusen goalkeeper.

"But it would have been simply irresponsible of me, my club and the national team to have participated in the World Cup. Medically speaking, it would have been possible. But the pain is so great that I would not have been able to perform at my best over the longer term both in training and during matches."

Having missed the last few weeks with the rib injury, Adler returned on Saturday for Leverkusen in their 1-1 draw with Hertha Berlin in the Bundesliga wearing a special rib protector.

But an examination by Germany team doctor Hans-Wilhelm Muller-Wohlfahrt has revealed the injury is worse than first thought.

Adler has already suffered a complicated rib injury which needed a titanium plate and four screws to repair in 2006 and nearly ended his career.

Germany coach Joachim Loew is set to name his World Cup squad tomorrow in Stuttgart and was informed of Adler's situation yesterday morning.

With Adler ruled out, Schalke's Manuel Neuer is set to take his place in goal for Germany's opening World Cup match in Group D against Australia on June 13 with Werder Bremen's Tim Wiese also travelling.

With Loew set to take three goalkeepers to South Africa, Bayern Munich veteran Hans-Joerg Butt could be set for a surprise recall nearly seven years after winning the last of his three caps for Germany.