A planned 10-day Olyroos training camp will take place just as Adelaide face Seongnam Ilwha.

The Olyroos are preparing for their crucial April 18 clash against Saudi Arabia...but the camp clashes with Adelaide's April 11 fixture - and would leave United without Nathan Burns and Bruce Djite.

"We'll be in heavy discussions over the next couple of days about that because yes, I understand that we want them to do very well for national teams but also we've got a responsibility here to play in the AFC Champions League," said United caretaker coach Aurelio Vidmar.

"We need to find a happy medium for both parties - I still believe if they play on the Wednesday and leave on the Thursday they'll still have five days to prepare.

"It's going to be tough … there's no question about that but the more you look after them and the more rest you give them, hopefully they will be able to perform at both levels."

The Reds have been struggling for personnel in their ACL campaign and, without Burns or Djite, may be forced to bring back injured Diego and Jason Spagnulo earlier than they would have liked.

United also have key players Ross Aloisi and Bobby Petta on the sick list, although both are desperately trying to get fit in time for the rest of the ACL schedule.

"Ross, besides rehab, hasn't done much since the grand final day so he's well away," he said.

"Bobby was going to be in our squad a fortnight ago but unfortunately he hurt himself on the Saturday before we left but I would think he's not too far away, it's another recurrence of his foot injury."