Sandown has put in contingency plans to stage an all-chase card on Saturday should the hurdles track be unraceable.
Clerk of the course Andrew Cooper described the hurdles track as "vulnerable" with more rain forecast on Friday. Officials at the Esher venue will have a look at the course on Thursday afternoon as well as take into account the latest weather forecast before making a decision.
Entries for the three extra chases will close at noon on Thursday with a decision on the hurdles course expected by 3pm.
Among the four races over the smaller obstacles are the Betfred Mobile Sports Contenders Hurdle, for which entries include last year's Champion Hurdle hero Rock On Ruby and Christmas Hurdle winner Darlan.
"If you don't make a start with your plans it becomes too late further down the line. It's a necessary stage and timing of the process if we are to give ourselves a chance. Our first and foremost objective is to try to run the card as scheduled," said Cooper.
"As is always the case here, the hurdles course is softer and more vulnerable. We've had about eight millimetres of rain in each of the last two nights.
"The thinking and the planning has to take into account the forecast. If it was a dry week you'd be pretty confident of staging the existing card, but we've got hanging over us the threat of really heavy rain on Friday. Up to 25mm is being indicated by plenty of forecasts we look at.
"To give ourselves the best chance of staging a race meeting here on Saturday the thought of putting on three extra chases was discussed. It was agreed that we provisionally got the process going and some entries in and we can take a view further down the line which course of action we take.
"We will take into account current ground conditions and the way the forecast is shaping up 24 hours down the line. It is going to amount to an inspection at 3pm to see which way we go."
22 May 2015Gleneagles tees off at Curragh
Stars storms Goodwood
Dettori receives golden ticket
Paris in Sandown shake-up
Tudhope suffers Haydock blow
Gatsby in great form for Gold run
O'Brien banking on Found progress
Ivawood targets Guineas revenge
Sole seeking home success
Brooch aiming to sparkle again
Dods hoping Angel can soar
Remote makes Festival return
Force back for Temple test
Cumani hangs fire as Dubai dazzles
Dods hoping for Angel delight
Epicuris team seek dispensation
Treve buzzing for Corrida comeback
No going concerns for Gatsby
Gleneagles spearheads Guineas field
Power to stay in Ireland
Muthmir earmarked for Haydock date
21 May 2015Ground concerns for Pretend
Ball back on duty at Worcester
Ground key to Boy Gold run
Fitz up against it for Galway
Hobbs to race in Godolphin blue
Haggas has plenty to Wonder about
Straight to Ascot for Rizeena
Curragh all set for big weekend
Byron in Greenlands hunt
Sandown or Epsom options for Spring
O'Brien looks to Tapestry
Europe the 'horse of a lifetime'
Legatissimo in Oaks reckoning
20 May 2015Top fillies given Irish Derby entry
Girl could spark Ascot dreams
Coolmore acquire Pharoah rights
Cirrus leads Longchamp septet
Time called on Europe career
Doyle set for Kazeem Gold run
RMG and ARC announce joint venture
Lyons planning dual Guineas raid
Albany aim for Spanish
Maarek team wait on ground
Birdcage takes flight at Dundalk
Gatsby tops Tattersalls entry
Great expectations in Needler
Karakontie likely to bypass Ascot
Devonshire added to Guineas field
Arod in Ascot frame
Elm team have high hopes
Varian retains Belardo faith
Ground to decide Power aim
19 May 2015Fanning targets swift return
Medrano camp turn to Hughes
Cossack named jumps champion
Toormore team get thinking caps on
Bear back on the move
Wind fired up for Temple test
Ballynagour makes French connection
Walker retains faith in Moon
Mimic in hat for Yeardley surge
Manhattan on menu for Protector
Pandora to swerve Oaks
Hannon duo primed for Guineas
Fabre rules out Lion Derby date
Weld respects Horn claims