Gethin Jenkins is facing a race against time to be fit for Wales' Six Nations Championship clash against Scotland at Murrayfield on March 9.
The Toulon prop suffered a calf muscle injury in last Saturday's 26-9 victory over Italy and subsequently returned to France.
The French club have said they expect the loosehead, capped 97 times, to be sidelined for 10 days, but he was due back with Wales 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 is standing by to replace Jenkins if the 32-year-old is ruled out, with interim head coach Rob Howley due to announce the starting line-up on March 5.
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 added.
"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."