McDonald came off the bench to score against Rangers on 3 January
Celtic have confirmed that striker Scott McDonald will undergo a hernia operation in the next few days.
The 26-year-old Australian will travel to Germany for what the club say is a minor operation and is expected to be out for no more than a few weeks.
McDonald has been the subject of interest from Barclays Premier League outfit Wigan during January.
But negotiations have broken down because the two clubs have been unable to settle on a transfer fee.
McDonald, signed for Celtic by Gordon Strachan, now manager of Middlesbrough, has faced added competition for a starting place following the summer signing of Marc-Antoine Fortune.
He was substituted by present manager Tony Mowbray shortly after 60 minutes of the recent defeat by Hearts and their victory over Hamilton Accies before finding himself named as a replacement for the 3 January Old Firm derby.
However, he came off the bench to score Celtic's opener in that 1-1 draw with Scottish Premier League leaders and reigning champions Rangers on 3 January.
McDonald, who has 15 caps for his country, began his career in Australia with Doveton before moving to Cranbourne Comets then to British football.
He made only two appearances for each of Southampton and Wimbledon and hit the net only twice in 20 appearances during loan spells with Huddersfield town and Bournemouth.
However, he sprung to prominence during three successful seasons with Motherwell in Scotland's top flight and that led to his £700,000 move to Celtic in 2007.
McDonald has now scored 64 goals in 127 appearances for Celtic and will be keen to resolve his injury problem and play regular first-team football to secure his place in Australia's squad for the World Cup finals in South Africa this summer.
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