Andy Murray does not feel he is ready to compete at the highest level after withdrawing from the Brisbane International.
Murray was set to make his return to competitive action in the second round against Ryan Harrison, having been sidelined since last year's Wimbledon quarter-final with a hip injury.
He played a one-set exhibition against Roberto Bautista Agut at the Mubadala World Tennis Championship last week.
But pain in the same hip has forced him to pull out of the tournament in Queensland, raising concerns that he will not be able to play at the Australian Open this month.
And the three-time grand slam singles champion hinted that could well be the case as he explained the reasoning for his absence.
"I'm very disappointed to be withdrawing from the Brisbane International," Murray said.
"I came here with every intention of making a strong start to the year, but sadly my team and I don't feel that I'm where I need to be just yet to compete at the highest level.
"I have great memories of playing here in Brisbane and I have always enjoyed competing in front of the Queensland fans, so look forward to returning in the near future."
The Briton follows Rafael Nadal in pulling out of the tournament, with the Spaniard now set to head to the Australian Open without having played a warm-up event.
Novak Djokovic's participation in Melbourne is also in doubt after his withdrawal from the Qatar Open because of an elbow problem that has kept him off the circuit since Wimbledon.