The Celtic striker believes his time in green and gold will come again but he doesn't want to risk putting his Celtic place in jeopardy.

McDonald recently penned a new five-year deal with the Scottish champions and he is anxious to remain firmly in Gordon Strachan's thoughts.

With plenty of competition for striking roles at Celtic Park, McDonald says it is vital that he is seen to build on last season's exploits.

He told the Daily Record: "It's a massive honour to be asked to represent your country at the Olympics and I know how disappointed I was to be overlooked by Australia four years ago when I was at Motherwell and they were going to the Games in Greece.

"It's the next biggest thing to the World Cup at international level but I had to turn it down because I would never want to put my place with Celtic under threat.

"The reason I signed a new five-year contract with the club was to be part of the major events, like the Champions League.

"There will be another time to play for Australia but no way back if I don't make a proper start to this season at club level. I jammed my foot in the first-team door at Celtic after signing a year ago and I don't want anyone to remove it."

McDonald has struggled to get off the mark in pre-season for Celtic but says it is the league where he should be judged.

"It would be a nonsense to judge me on what's happened so far. A lack of goals in July doesn't count. What happens in August when the championship defence begins is what's important. And they'll come, I'm sure of that," he said.

The Australian has also vowed to carry on being a happy Mr Grumpy this season.

He said: "Everybody knows I'm the biggest moaner at the club. The manager takes advantage of that and rips me up in front of the other boys at regular intervals.

"I know I can embarrass myself at times and the gaffer cracks jokes at my expense whenever I go over the top."