Bayern Munich CEO Oliver Kahn has described the search for a replacement for the injured national goalkeeper Manuel Neuer as "extremely difficult".
"Not many clubs would like to give up their number one," Kahn told the Bild newspaper.
Gladbach's Yann Sommer is the record champion's dream solution.
But Alexander Nübel, who was loaned to Monaco, should still be an option.
Board member for sport Hasan Salihamidžić confirmed his interest in summer for the first time before leaving for the training camp in Qatar.
"I don't like to talk about players from other clubs, but it's definitely an issue, of course," he said on Sky.
Kahn remains calm: "In Sven Ulreich we have a reliable, top-class goalkeeper who is familiar with this situation.
Hasan Salihamidžić, Julian Nagelsmann, Marco Neppe and I are discussing various options without hesitation.” According to Salihamidžić, “a decision will be made in the near future”.
Neuer is expected back in the summer after breaking his lower leg, the Bayern captain will then be 37. “We hope that this rehabilitation period will go without complications.
But football is a short-term business, we have to think about the here and now,” said Kahn.
The Bayern boss did not want to answer directly whether Neuer would still be the undisputed number one in the summer: “We know Manuel: He will do everything to get back in top form.
And a Manuel Neuer in top form is still absolutely world class.”
Bayern left for Qatar on Friday morning.
In Doha there should also be talks between those responsible and the controversial partner Qatar Airways.
The fans have long been demanding an end to the partnership, but Kahn once again left everything open.
“First of all, it will be a matter of taking stock and then re-assessing each other's interests.
We will discuss sporting, economic and social issues,” he said: “There will be no water level reports on this.”