Gethin Jenkins could face a race against time to be fit for Wales' RBS 6 Nations clash against Scotland at Murrayfield next week.
The Toulon prop suffered a calf muscle injury in last Saturday's 26-9 victory over Italy.
The 97 times-capped loosehead subsequently returned to his club, who have said they expect him to be sidelined for 10 days, but he was due back with Wales today for further assessment.
"We will find out a bit more when he arrives here and the physios can cast an eye over him," Wales assistant coach Robin McBryde said.
"It is going to be a close call. We will have to see how he responds to treatment."
Bath prop Paul James would undoubtedly replace Jenkins if the 32-year-old is ruled out, with interim head coach Rob Howley due to announce the starting line-up next Tuesday.
Howley is also likely to look at the second-row, where a fit-again Alun-Wyn Jones could dislodge Andrew Coombs, while Sam Warburton will challenge strongly for a back-row recall.
"I think there will be a couple of selection issues," McBryde said.
"As much as we benefited from keeping the same team (after France) for Italy, there were certain areas we are always looking to improve upon.
"We have got strength in depth to choose from, so I dare say there will be a few discussion points."
Coombs possibly missing out against Scotland would be tough on the Newport Gwent Dragons forward, given how much he has impressed in Wales' three Six Nations games so far during his debut international campaign.
But the all-Ospreys second-row pairing of Jones and Ian Evans is arguably Wales' strongest as they prepare to face Scotland and then England with a successful Six Nations title defence still possible.
"You never know how someone is going to react on their debut when given the opportunity, and I think Andrew has surprised everybody," McBryde said.
"He has been very accurate in the work he has done. He rightly held on to his jersey for the last game.
"You are always looking to see where the next player in line is going to come from, and Andrew Coombs has shown there is more talent out there."
McBryde has no doubt it will take a strong collective effort from the Wales forwards in Edinburgh after Scotland's pack shone during a tense 12-8 victory over Ireland last time out.
"They dug in, didn't they," said McBryde, reflecting on a win that kept Scotland in with an outside chance of silverware.
"Scott Johnson (Scotland coach), after the game, was honest in saying the pressure probably turned on Ireland once they couldn't see the scoreboard ticking over.
"It was a good performance, and I am sure the victory has galvanised them even more, knowing they weren't at their best yet they've come away with a victory.
"They are going to be buoyed by that, and I think they will be a bit more confident when we face them a week on Saturday.
"Their scrum has been very much a weapon for them. They've scrummaged extremely well and been very strong in the set-piece.
"Jim Hamilton deserved the man-of-the-match award last weekend because he disrupted so much of Ireland's possession, and we all know how effective Richie Gray is.
"They are quite an astute bunch of forwards and Dean Ryan (Scotland forwards coach) is there having his influence as well. It's going to be a challenge for us."
Wales, though, put their house in order against Italy, destroying the Azzurri's scrum following inconsistent performances in the appointments with Ireland and France, and a repeat performance at Murrayfield could cause Scotland problems.
"We carried out what we said we were going to do," said McBryde, reflecting on the efforts in Rome.
"There were issues we had to address and get our own house in order, and that's what we did. In fairness to all the players, they were very honest and up-front following the first two games.
"It was very easy for me as a coach to sit back, let them do all the talking and take a lot more ownership over their individual roles, their mini units and as a pack of forwards.
"You saw the benefits of that against Italy, but we are going to have to be at our best again against Scotland. They've posed quite a few problems to all the teams they've faced."
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