Hobart: Venus Williams withdrew from the Hobart International on Sunday less than 24 hours after losing the Auckland WTA final.
"I don't believe she has an injury," tournament director Mark Handley said. "I just think that she's played a lot of tough, close matches over in Auckland and in the lead-up to a first Grand Slam (of the season) she's not taking any chances."
Williams was planning to use the Hobart event as final preparations for the Australian Open which begins Jan. 13. She lost in the third round at Melbourne Park last year.
The 33-year-old Williams lost 6-2, 5-7, 6-4, to Ana Ivanovic at Auckland on Saturday. It was Williams' first final since winning her 44th career title at Luxembourg in October 2012.
The seven-time Grand Slam champion's ranking has fallen to 47th as she has battled injuries and Sjogren's syndrome, a fatigue-causing autoimmune disease, over the past two years.