Agger has missed most of this season through injury and is currently sidelined with a knee problem picked up in Liverpool's Europa League win over Sparta Prague. Olsen admits he has serious worries about whether Agger will be able to play for Denmark in their European Championship qualifier in Norway on March 26th.
"Right now we can only wait, but I must admit that Daniel Agger is doubtful for the international match. Daniel has not played for a while now with his knee injury and we do not really know whether he is ready – and in what form he will be in," said the Danish boss.
"It's frustrating for Daniel, Liverpool and certainly for the national team before the crucial match in Norway, but we must just wait and see what happens.
"I have an agreement with Liverpool’s club doctor that we should talk one day, but he is certainly not ready yet and it is extremely worrying."