Ireland and Munster lock Paul O'Connell's last game was against Scotland in the RBS 6 Nations
Munster captain Paul O'Connell and Irish international teammate Keith Earls face a battle to be fit in time for the Heineken Cup semi-final against Biarritz after both were omitted for Saturday's game against the Ospreys.
O'Connell has not played since Ireland's RBS 6 Nations defeat to Scotland while versatile back Earls is also suffering with a groin problem.
But although they will not feature in their key Magners League clash with the Ospreys, team manager Shaun Payne believes they will return in time for their trip to France.
He said: "We need them training. They can't go into a game with any preparation at all.
"It's an injury that needs rest and the more you load it the worse it's going to get.
"We'd be confident that both of them will be available, but these are difficult injuries and they are very frustrating for us to have to deal with. There is obviously a situation where there will be a cut-off point."
Ireland Under-20s may be the only unbeaten side after two rounds of this year's Under-20s Six Nations, but full-back Billy Dardis believes this weekend's clash with England will be a step up from anything that has come before.