World number one Lleyton Hewitt has expressed surprise at Greg Rusedski's unavailability for the upcoming Davis Cup match between Australia and Great Britain.
The British number two withdrew from the team to face Australia in the first round in February, citing a foot injury.
But Rusedski is playing in Doha at the beginning of January before deciding whether to enter the Australian Open.
"It is very weird, I struggle to see how a guy can pull out and say he is injured and he is playing in Doha on Monday," Hewitt said.
"I am sure the British people are a little shocked with it all, and I am sure the team is very disappointed," he said.
Hewitt said it would be disappointing for the Sydney fans if Rusedski and Henman were unavailable.
"Potentially it could be a fantastic week of tennis if we have myself and Mark Philippoussis playing against Rusedski and Henman," he said.
Meanwhile, British Davis Cup captain Roger Taylor has refused to be drawn into the debate over the future of Rusedski.
Rusedski's decision has led to speculation that the 29-year-old may have played his last Davis Cup match.
However, Taylor, who is now hoping Henman can recover from a shoulder injury in time for the Australia clash, said he would not make any "rash statements" about Rusedski's future.
"I can't say if this is the end of Greg's Davis Cup career," Taylor said.
"Would I rule him out of future team plans? Of course not. It would be foolish to make rash statements like that.
"You will really now have to ask Greg where he sees his Davis Cup career going. I notice in his statement he says he is unavailable for 'this particular tie'."
Rusedski pulled out of Britain's relegation showdown with Thailand in September, forcing the team to call up British number 14 Miles MacLagan.
"I don't want to put the Davis Cup team in a difficult position by giving them last-minute notice if I had to withdraw," Rusedski said.
"I'm not sure how my foot will react in Doha, let alone the Australian Open. The surgeons warned me that it would take four to six months to recover from the operation.
"I'm going to Doha with a completely open mind, having just got back to training within the last two weeks."
Britain have not won a World Group tie in the competition since 1986 and defeat in Sydney would condemn them to yet another relegation play-off.