Sean O'Brien will start Ireland's RBS 6 Nations clash with England despite having spent last week in hospital recovering from a skin infection on his foot.
O'Brien returned to training on Monday and coach Declan Kidney is confident the reigning European player of the year will be ready for the climax to the tournament at Twickenham.
A course of antibiotics was needed to treat the infection and O'Brien lost two kilos while ill.
Munster openside Peter O'Mahony, who impressed on his full debut in Saturday's 32-14 rout of Scotland, drops to the bench to make room for the 25-year-old.
"Sean trained well this morning and we wouldn't have selected him if he wasn't ready," Kidney said.
"It's tough on Peter because he played really well against Scotland."
It is the only change to the side that condemned the Scots to a wooden spoon decider against Italy.
Captain Rory Best (ribs) and lock Donnacha Ryan (shoulder) have been included despite carrying injuries that will limit their involvement in training this week.
Best will become Ireland's most capped hooker when he makes his 59th Test appearance, eclipsing Keith Wood's milestone of 58.
Ireland have won seven of their last eight Six Nations matches against England, including three of the last four meetings at Twickenham.
The contest is likely to decide who finishes runners-up with Ireland ending the competition strongly by thrashing Italy, drawing with France and blitzing Scotland.
A big performance from England would further strengthen Stuart Lancaster's claim to being named permanent head coach. England name their team on Thursday.
Ireland: R Kearney (Leinster); T Bowe (Ospreys), K Earls (Munster), G D'Arcy (Leinster), A Trimble (Ulster); J Sexton (Leinster), E Reddan (Leinster); C Healy (Leinster), R Best (Ulster, capt), M Ross (Leinster), D O'Callaghan (Munster), D Ryan (Munster), S Ferris (Ulster), S O'Brien (Leinster), J Heaslip (Leinster).
Replacements: S Cronin (Leinster), T Court (Ulster), M McCarthy (Connacht), P O'Mahony (Munster), T O'Leary (Munster), R O'Gara (Munster), F McFadden (Leinster).