The Edinburgh forward limped off early in the second half with what was initially described as a “tight calf” but that has now been upgraded to a “tear”.
The prop, who has been back to his best after battling neck and arm injuries in recent years, has not been officially ruled out of Saturday’s visit of the world No 2-ranked Irish but the noises from the Scotland camp yesterday were not encouraging.
Scotland assistant coach Mike Blair reported: “When he went off it was a precaution, originally, and he just tightened up a bit.
“That’s when the information came back about the tear, so it will just be a little bit of time. Some people react quickly to it, some people don’t. You don’t really know.”
Scotland added Glasgow hooker Fraser Brown and Edinburgh prop Murray McCallum to their Six Nations squad yesterday.
Brown, who has missed a couple of months with a knee injury, joined the group at their Oriam base in non-contact training last week and trained fully yesterday, with fellow Warrior and hooker Grant Stewart released back to his club.
Exeter Chiefs forward Sam Skinner injured his ankle early in the first-half of the Italy game and, as expected, will play no part against Ireland as he returns to his club for further assessment.
There was brighter news on the trio of lock Jonny Gray (shoulder), wing Sean Maitland (hamstring) and centre Peter Horne (knee), all of whom look to be available for selection this weekend against and Irish side smarting
from their home loss to England.
Blair said all three were set to train yesterday afternoon.
The loss of 32-year-old scrum linchpin Nel, pictured, would be a big blow for Scotland but his Edinburgh front-row clubmate Allan Dell said the team will be able to cope.
“WP is a very experienced tighthead. We have played in the Six Nations without him before,” said the loosehead. “Simon Berghan I assume will come in and fill the three jersey. He has played well for Edinburgh and he has played well for Scotland at tighthead.”
Dell couldn’t deny the fact that Nel’s absence is not ideal. “That experience and aggression that WP brings to the front row will be sorely missed, I feel,” he admitted.