Doncaster clerk of the course David Williams admits the likely deluge of rain that is due to hit the track this week will have a significant effect on the going.
The four-day St Leger meeting gets under way on Wednesday and although the ground is currently described as good to firm, that looks certain to change in the next 24 hours.
"During Monday evening and overnight into Tuesday, we could get anything between 20 and 30 millimetres of rain," Williams told At The Races.
"We could see some more light rain on Friday, amounting to seven or eight millimetres, so we're hoping that doesn't go into Saturday.
"The ground is good to firm at the moment and we've basically been keeping it ticking over for the last three weeks.
"It's been dry for much of the year and we've pretty much had a drought here, so it would be nice to see some rain - just not that amount.
"It's certainly going to be on the easier side of good and I think the ground is going to be pretty cut up by Saturday."
