Andy Murray will miss the Australian Open after failing to recover in time from an injury picked up at the Davis Cup finals last month.
The 32-year-old's contribution to Great Britain's efforts in Madrid was restricted to one match after he suffered a problem with his pelvis.
It was initially thought the issue was minor and would not affect his participation in either the season-opening ATP Cup or the Australian Open, which was set to be Murray's grand slam comeback.
But alarm bells rang when he cancelled his training block in Miami and on Saturday night his management company announced the Scot would not be travelling to Australia.
Murray is now back on court but, given it is still relatively early days in his comeback from hip surgery in January, his team made the decision not to rush his return to competitive tennis.
There will therefore be no emotional return to Melbourne Park a year on from the press conference in which he revealed the extent of his hip problems and contemplated retirement.
A remarkable five-set loss to Roberto Bautista Agut followed in what he accepted could have been the final match of his career.
But two weeks later he underwent hip resurfacing surgery that removed the pain that had dogged him for two years and enabled him to begin a tentative comeback at Queen's Club in June.
By winning the European Open in Antwerp in October, Murray raised hopes that his days as a contender for the biggest titles may not yet be finished.
But he will not play a match until February at the earliest, with his first tournament now scheduled to be the Open Sud de France in Montpellier beginning on February 2.
Murray's announcement also means he will not be part of the Great Britain team at the ATP Cup in Australia, which starts on January 3.
Murray qualified Britain for the inaugural edition of the team event through his protected ranking of world number two but Dan Evans and Cameron Norrie will now carry the responsibility in singles.
Britain play group matches against Bulgaria on January 3, Belgium on January 5 and Moldova on January 7, all in Sydney.