Leinster have been dealt a blow as they look to secure Magners League glory and retain their European crown.
The Dubliners will be without star full back Rob Kearney for between three and five weeks after he picked up a knee injury last weekend.
And although Kearney would have been away with Ireland for much of that time period, it means his next appearance in the Magners League could come after limited time back on the training field.
"Rob Kearney is rehabbing and is out for England," said Ireland coach Declan Kidney.
"We’d always give it 48 hours before confirming, but we expect him to be out for between three to five weeks."
Kearney will definitely be unavailable for Ireland’s trip to Twickenham a week on Saturday and, although there is still a chance he could feature against Wales on March 13 or Scotland on March 20, it is feared he may miss the remainder of his country’s Six Nations defence.
If Kearney fails to recover before the end of the Six Nations, a possible return date could be the March 27 Magners League clash with Connacht at the RDS.