SONIA O'SULLIVAN was at the centre of further speculation yesterday after she had withdrawn from tomorrow's international meeting in Monte Carlo.

The announcement came just hours after a spokesperson for her agent, Kim McDonald, said that she would "probably run" at the meeting before travelling on to more important assignments in Zurich and Cologne next week.

The amended statement said: "Sonia will not now compete in Monte Carlo. She is training twice a day and a decision on her future plans will be announced at a later date."

It is understood that, in the period between the issuing of the two statements, the athlete went for a run near her home in London where she has been in training since returning from Atlanta.

She is understood to have undergone further medical tests since her surprising eclipse in both the Olympic 1,500 and 5,000 metres championships but the results of these have not been disclosed.

The effect of this latest development will be to raise still more doubt about the remainder of her seasonal programme and, in particular, next Wednesday's big meeting in Zurich which will feature many of the recently crowned Olympic champions.

Zurich is the second of the series of meetings which determine the winners of the Gold Bars awards scheme which has proved so lucrative for O'Sullivan in recent seasons. She won her event in the opening meeting in Brussels last month but would automatically forfeit her chance of sharing in the awards if she opts out of next Wednesday's assignment.

To that extent, it may well hold the key to her programme over the next four weeks. If she runs and does well there, the likelihood is that she will fulfil most, if not all, of her remaining engagements.

If, on the other hand, she is forced to withdraw, it may well precipitate an announcement that she intends to take a longer break from competition.