Ireland flanker Peter O'Mahony faces a battle to be fit in time to take on Italy in Dublin after suffering a hamstring strain in Saturday's 13-10 England defeat.
The IRFU has confirmed the 24-year-old loose forward damaged a hamstring in the RBS 6 Nations third-round clash at Twickenham.
Ireland host Italy in round four on Saturday March 8 and the Munster back-rower will already be working flat out to be fit to take part.
Stalwart centre Brian O'Driscoll suffered cramp in his calf in the latter stages of the England defeat.
The IRFU labelled the 35-year-old "very focused on his recovery" and he will be monitored by the medics throughout the week.
O'Driscoll should have no problems finding fitness for the Italy clash, provided he has sustained no damage to his calf other than the cramp that forced him off the field in the closing stages at Twickenham.
Ireland head coach Joe Schmidt paid tribute to O'Mahony for being "pretty generous with his body" in the wake of Saturday's defeat.
The former Leinster coach will want the abrasive operator fit for Ireland's Six Nations run-in, especially with the title still on the line.
"There are only so many seconds you can stay on the ball and be hammered away at without it taking its toll, and I thought he held on for two or three seconds at a time," said Schmidt of O'Mahony's bravery at the breakdown.
"If you don't get the reward there are certainly a few bruises to show for it."
Ireland's squad will meet on Wednesday for a two-day training camp in Belfast.
Ireland's loss to England means no team can claim a Grand Slam this season, but Schmidt's side can still steal the title.
England, Wales and France could all yet grab championship glory, though, leaving Schmidt circumspect about Ireland's silverware chances.
After victories over Scotland and Wales, Schmidt said the England defeat means Ireland can ill afford to look any further than facing the Italians.
"The title might become a carrot if we can take care of Italy," said Schmidt.
"We have to try to build piece by piece, especially when you trip up.
"We'd taken two good steps, but to trip up on this one, we don't want to then try to take a giant leap, because you're not in as strong a position.
"You just want to make sure the next step is firmly planted, secure, and we'll work towards that over the next two weeks.
"You cannot come to Twickenham, roll your sleeves up like that and not feel proud of the people that put 100 per cent into it.
"Afterwards they felt frustrated and disappointed, and the least I can do is feel proud of the effort and endeavour.
"We're trying to help ourselves along though, so we'll have a pretty forensic look at it, and be fairly brutal with each other about what we need to get right.
"At the same time we'll be pretty positive about that effort and endeavour, and a number of the things we did pretty well."