Northampton Saints will not risk George North in Saturday's European Champions Cup quarter-final at Clermont Auvergne after he suffered a head injury last week.
The Wales international was knocked out while scoring his second try during last Friday's 52-30 Premiership win over Wasps.
North missed Wales' Six Nations clash against Scotland in February after suffering concussion in the tournament opener against England and is now seeking advice from a specialist.
"We won't play him at the weekend. Clearly he had a nasty knock," Saints coach Jim Mallinder said.
"He's making good progress. The day after he was up and about.
"He's improving and down there at the moment going to see a neurologist. We'll wait to see what the experts say.
"I think you have just got to be careful not to get too carried away.
"There are a lot of so-called experts out there giving amounts of weeks and months that players should be out.
"You need to look at every single player individually, you have got to know what their medical record is and what has happened in the past.
"That's what the specialist knows. He has got all that detail, and he'll make his specialist opinion, and we will be fully guided by that."