With little more than a week to go before the start of Andy Murray's planned comeback tournament in Brisbane, concerns are growing he is behind schedule in his preparation because of lingering problems with his damaged right hip.
Murray has not broken down physically, and is understood to be continuing his training programme with Jamie Delgado, his coach, at the All England Club's facilities in Wimbledon.
However, it is a surprise - and a worrying one, for British tennis fans - that he is in the UK at all.
The original intention had been for Murray and his family to travel to Australia before Christmas, to give him the fullest possible preparation for the tournament.
As he put it at his exhibition event in Glasgow six weeks ago: "My plan is to do a couple of weeks in Miami and then go to Australia very early, much earlier than I have done in the past."
But when you consider that it takes the best part of 24 hours to travel to Australia, Murray is no longer in a position to establish a base camp for a lengthy period of acclimatisation. Increasingly, it feels as if he is in a race against time to get there at all.
"Coming into the beginning of the new year, I will be at a bit of a disadvantage because I have not played matches for a long time," Murray said in Glasgow. "So, if I can go there a little bit earlier to get used to the conditions, a bit sooner than some of the other players, that might help level it up a little bit for me."
Such levelling seems unlikely to be achieved. Indeed, Murray is understood not to have begun playing practice sets with top-100 level players - the usual procedure for anyone building up to an ATP event. Instead, he is still working his way through drills in his methodical, conservative way.
None of this is to say that Murray has given up hope of featuring in Australia, whether in Brisbane, starting on December 31 or in the Australian Open that begins on January 15.
Murray has consulted a wide variety of hip specialists and has encountered a mixture of opinions, some of them less than optimistic.
One particularly hard-line expert is understood to have told him that his time at the peak of the game has already run its course.
Despite that assessment, the plan of appearing in Australia is still very much alive, according to Murray's management team, but chinks of doubt are appearing.
Were he not to make the cut, it would feel like a significant blow, especially as he has not appeared on the match court since Wimbledon.
Murray, now 30, has decided against surgery, preferring rest and lots of rehabilitation.
Pessimists argue that a degenerative hip will not recover, no matter how much of a break you have away from the circuit.