Published: Dec 16, 2011 3:33 AM EST
Updated: Dec 16, 2011 7:30 AM EST

MELBOURNE, Australia (AP) - Defending champion Stuart Appleby has withdrawn from the Australian Masters due to a back injury.

Appleby shot a 1-under 70 in the opening round at Victoria Golf Club on Thursday, five strokes off the lead. He said he decided before teeing off for the second round on Friday that his injury was too painful for him to continue.

The Australian said earlier in the week that with rest and continued treatment he would be fit to resume playing when the U.S. PGA Tour gets under way next year.

Ian Poulter of England was the overnight leader after shooting a 6-under 65 on Thursday.