George North ruled out of Northampton's Champions Cup clash after third concussion of 2015
Wales wing George North will not play for Northampton in Saturday's European Champions Cup quarter-final at Clermont Auvergne after his latest head injury.
North has been knocked unconscious three times in recent months, including in last Friday's 52-30 win over Wasps.
Saints coach Jim Mallinder said: "We won't play him at the weekend. Clearly he had a nasty knock.
"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 and we'll wait to see what the experts say."
Former World Rugby medical adviser Dr Barry O'Driscoll says North - the top try-scorer in the competition with seven this season - should not play again this season.
Mallinder added: "There's been lots of opinion. We've got to be careful that we don't blow anything out of proportion.
"It's a tough game, (but) player welfare will always come first."
Here is the incident: