A fragile display during the 26-21 defeat by France resulted in Murphy initially being jettisoned from the 22 for Saturday's RBS 6 Nations clash at Croke Park.

But first choice full-back Girvan Dempsey sustained bruising to his left hip in training on Thursday and when he failed a fitness test this morning, Murphy was handed a late reprieve.

Frustratingly, the supremely gifted 29-year-old has not always emulated his brilliance for Leicester in a green shirt, proving error-prone and vulnerable in defence.

With Dempsey laying an unshakeable claim to the number 15 jersey, he has been shunted onto the wing by Ireland and makes no secret of his preference in position.

But having been restored at full-back, O'Driscoll - who passed his own fitness test this morning - has urged his enigmatic team-mate to seize his opportunity.

"It's rare that Geordan is in bad form. I find it exciting being on the same training pitch as him. He can do some phenomenal things," he said.

"More often than not he's the most skilful player on the pitch. That creates great excitement and anticipation.

"It's a great opportunity for him to play at full-back because I know he prefers that position to the wing."

Dempsey has probably been Ireland's most consistent player over the past 12 months yet amazingly there remain calls for Murphy's selection ahead of him.

The logic behind demoting the unfairly-maligned Leinster veteran is unfathomable, but once injury had struck Ireland coach Eddie O'Sullivan had no hesitation in turning to Murphy.

Having been included in Leicester's squad to face Sale on Saturday, Murphy jetted back to Ireland on Thursday with O'Sullivan deciding his familiarity would be key at such a late stage.

"Girvan didn't make it. It wasn't a bad injury, it was just the timeline was too tight," he said.

"He took a knock to the hip and there's a bit of bruising there. There's bit of a twinge as well.”

Dempsey may be lamenting his poor fortune but fate smiled on O'Driscoll, who was given good news on his tight calf this morning.

The Lions skipper picked up the niggle during training on Tuesday but has made a complete recovery.

"There was always an element of concern but I felt great this morning," said O'Driscoll.

"You get these knocks throughout your career and sometimes you know when it's going to be a problem, but I always felt I'd get through this."

Ireland could ill afford to lose O'Driscoll, even against a ponderous Scotland side that has suffered two successive defeats in the Six Nations.