Australia's head swimming coach Alan Thompson wants Ian Thorpe to make up his mind about competing in next year's world championships in Canada.
Thorpe has won three successive world titles
Thorpe is considering skipping the meeting to give his body a break as he prepares for the 2008 Olympics.
He told the Sun-Herald newspaper he would not race in Montreal unless he was in shape to do his best.
"Ian has got to decide what is the best way he can ensure he gets the best out of himself," Thompson said.
With the Australian selection trials less than three months away, Thompson is keen for Thorpe to make a decision.
"He has got to do what is best for his performance, and if missing the world championships is the best, then I will
"Ian has to make sure he gives us his best when it really
matters. I would like to have Ian swimming at his best in 2008 at the Beijing Olympics."
Thompson said that Thorpe's absence would give other swimmers a chance for invaluable experience.
"I think rather than look at the negative we should look at
the positive and it will give younger guys the opportunity to come through," Thompson said.
"It is an opportunity for someone else, as opposed to
someone not doing it."
If the 22-year-old decides not to compete, he will miss the chance to become the first man to win four straight 400m freestyle world titles.
Thorpe holds the world freestyle records at 200m, 400m and 800m but says he believes his best is yet to come.
"That is what keeps competition interesting for me and I will know it when my best performance comes," he said.
"I will just feel it. I'll also know when it is time to stop swimming. If I stop enjoying it, the answer will be simple."