McDonald did not play in Celtic's 2-1 win over Hamilton yesterday morning and his manager Gordon Strachan said immediately his player would not be available for the match.

''He won't fly. It's impossible with the virus to get on a plane and be in that restricted area for that amount of time and then go out in the heat and try and train,'' Strachan said.

Socceroos officials were expected to announce overnight whether or not McDonald would fly to Bahrain.

If he is ruled out he would become another in a growing list of casualties for the Socceroos with Brett Emerton, Vince Grella, Craig Moore, Matthew Spiranovic and Mark Milligan already ruled out of the squad due to injury or illness.

Australian captain Lucas Neill said complacency wouldn't be an issue against Bahrain despite the Socceroos having already established themselves as the team to beat in the final stage of World Cup qualification.

Australia heads into Thursday morning's qualifier in Manama sitting pretty atop its group with wins against Uzbekistan and Qatar in its first two matches.

Another precious away win would be a giant leap towards qualification for South Africa 2010.

Although facing a short and disjointed preparation, the Socceroos are firm favourites against a Bahrain side placed fourth in the five-team group with just a solitary point.

But Neill has warned his side cannot take the challenge lightly and said there would be ''no excuses'' for anything but another business-like performance.

''I think this is going to be a very tough game,'' the West Ham skipper said after Australia's first training run yesterday.

''Obviously the fact we've put ourselves out in front now, we're there to be beaten.

''But I think the response from a professional approach has been fantastic in the first two games and we'll be looking to do exactly the same again. There won't be a chance for complacency because the manager and I won't allow it.