It means Whitehaven's scheduled League One trip to Hunslet will have to be played at a later date.
Hunslet, who are coached by former Whitehaven coach James Coyle, put up a gritty show at Championship side Halifax in their Challenge Cup tie and went down 20-6 – losing the second half, 8-6.
With Oxford not happy about travelling in midweek, and little time before the fifth round, the RFL made the decision and told the clubs to arrange the tie for this Sunday.
The Recreation Ground, which had been very heavy after the Toronto game on March 12, was made worse by heavy rain.
So it was declared unfit for purpose on Saturday lunch-time.
The fifth round draw for the Ladbrokes Challenge Cup was made on this morning’s BBC 5Live Breakfast show, where the special guest was ex-Wigan and England star Jason Robinson, with Haven or Oxford drawn at home to Halifax.
Without presuming anything, Haven coach Carl Forster had already said that if his side goes through, the preferred tie would have been Leeds Rhinos away – to make some money for the club’s coffers.
Oxford won’t be using Castleford forward Alex Foster against Haven on Sunday after he suffered an injury in the last League One game against Workington Town.
He has just come back from a hernia operation but, against Town where he was one of the most effective forwards, he suffered a tear in his pectoral muscle which will put him out for a few weeks.
Ex-London Broncos and Leeds forward Foster is on trial at Castleford and because the Tigers wanted him to get game time allowed Oxford to use him.
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