Northampton have stood down George North for their Champions Cup quarter-final against Clermont Auvergne after the wing suffered a third concussion in the space of eight weeks.
The Wales star is consulting a neurosurgeon to assess whether he can play again this season.
North was knocked unconscious in the first half of Northampton's victory against Wasps when Nathan Hughes' lower leg struck North's head as he was scoring a try. Hughes was red carded and subsequently suspended for three weeks.
"We won't play him at the weekend," Jim Mallinder, direcort of rugby said. "Clearly he had a nasty knock. It was unfortunate. He did get knocked unconscious for a very short period of time.
"Thankfully he was well looked after, he came round very quickly and has had no real bad adverse after-effects. But even so, we won't play him this weekend.
"Seeing as it's not his first then it's the sensible thing to take specialist opinion." (© Daily Telegraph, London)