The Dons were already braced for being without injured pair Lewis Mayo and Mats Knoester through injury while Dan Happe is suspended after being sent off in the quarter-final victory over Kilmarnock.

But right-back Chris Cadden has now been ruled out after sustaining a minor hamstring injury in Wednesday’s defeat by Falkirk, while centre-back Kristers Tobers – who only returned to the squad against the Bairns after 13 months out – has suffered a setback.

Asked about his defensive situation, Robinson said: “I’m too scared to answer. Yes, we’ve got a problem at the back, with Lewis, Mats, Dan being suspended, but he’s actually ill as well.

“Tobers has had a little bit of a setback. He’s got a little bit of swelling on the knee, so he won’t be available for selection tomorrow.

“Chris Cadden won’t be available tomorrow either.”

It means Aberdeen will be missing four of the five defenders who started the quarter-final victory over Kilmarnock last month, paving the way for a potential first start of the season for Nicky Devlin.

“We haven’t had our troubles to seek, but somebody’s misfortune is somebody else’s opportunity,” said Robinson.

“It’s a chance for people that maybe haven’t had opportunities, a chance for people that haven’t been fit, to stand up and be counted and there’s no better stage than Hampden to do that.”

Aberdeen go into the semi-final under a cloud after losing three of their four matches since the international break, cranking up the heat on Robinson.

Robinson said he had not sought any assurances about his position from the Dons hierarchy as he pointed out that there is “no better place to turn it around” than a Hampden semi-final against Rangers.

“We know the results over the last couple of weeks haven’t been good enough. Simple. No one’s getting away from that fact,” said former St Mirren boss Robinson, aiming to maintain his perfect semi-final record as a manager.

“There was a good performance in that as well (the 3-1 win over St Mirren), but ultimately, we deserve the criticism, we can’t get away from that. I deserve the criticism.

“I don’t hide behind that. I don’t try and throw players under the bus. I deserve that and we have to respond to that.”

Robinson has called on Aberdeen to embrace their underdog status.

“Obviously we come up against a team that are in form,” he said. “I’ve been to semi-finals before and I’ve always been the underdog. No doubt that will be exactly the same, but it’s up to us to turn that around.

“I’ve proved that we can do that as a staff. And some of the players have been to finals previously and won, so they’ve got that experience.

“Certainly there’s enough experience in the room between the staff and the players to cause an upset, which it would be.”