Saracens and Saxons flank Will Fraser has been called up to the England squad as injury cover for Ben Morgan.
Morgan damaged his ankle in the 38-18 win over Scotland on Saturday, with a verdict on his fitness for the coming weekend's fixture against Ireland in Dublin due on Tuesday.
Stuart Lancaster told BBC 5 Live that England would in all likelihood move flanker Tom Wood into the number eight slot, with Wasps back-row forward James Haskell coming in at blindside flanker. Another Wasps player, number eight Billy Vunipola, is also in contention.
"Will Fraser of Saracens will join squad as cover for Morgan, Lancaster was impressed with his performances in both Saxons games," said the RFU on Twitter.
"Lancaster says Ben Morgan's ankle is "still in a boot", likely prognosis is No.8 will struggle to make Ireland v England. Definitive news tomorrow."
Meanwhile, England have been handed a boost with the news that outside centre Manu Tuilagi is available for this weekend's clash with Ireland at the Aviva Stadium in Dublin.
"The last message we had about Manu was that he's fit and available to train. He's coming in this afternoon. He's available for Sunday," Lancaster said.