Saturday's Irish 2,000 Guineas card hinges on a morning inspection following a deluge of rain overnight.
The Curragh Racecourse was hit with 35mm – far more than what was forecast.
As a result, the track is waterlogged in places a day ahead of the Tattersalls-sponsored feature race.
Fans will have to wait and see whether English 2,000 Guineas winner Poetic Flare and third Lucky Vega can renew rivalry at the County Kildare venue.
Officials will check conditions at 7.30am on Saturday morning.
Pat Keogh, chief executive at the Curragh, said: "We got lot more rain than we anticipated overnight. We were forecast 15 millimetres at the most in the last 24 hours, and got 35 millimetres.
“It’s come completely out of left field, unfortunately.
“The track would not be raceable today. Most of the track is raceable, but there are a few areas (that are waterlogged) and we will look to get that off the track.
“We’ll just have to monitor things as we go along. If more rain came than was forecast that would give us a problem.
“We’re hopeful, but we will have a precautionary inspection tomorrow morning.”
Three further Group races are scheduled on the card, while Sunday's programme features the Irish 1,000 Guineas and Tattersalls Gold Cup.
Friday’s jumps cards at Wexford and Downpatrick go-ahead after ground concerns eased.
