NORTH Melbourne's concussion concerns have deepened with forward Kayne Turner ruled out for the remainder of Sunday's clash with Sydney.

Turner had an accidental brush with the knee of Swans defender Dane Rampe in the opening stages of the match before he was taken down to the rooms for assessment.

The decision to keep Turner out of the game came after a flurry of activity on the North Melbourne bench between football staff and medicos.

As Turner remained in the rooms for his minimum 20-minute assessment period, medical staff re-watched the incident with Rampe for further clarification on his availability.

Head of football Cameron Joyce was in strong conversation with club doctors as the Roos' coaching staff demanded answers on his potential return.

A short time later, Turner returned to the bench where he was told his day was over.

It came after midfielder Ben Jacobs was a late withdrawal pre-match with concussion symptoms and neck soreness.

It was the third match in four weeks that Jacobs has missed due to concussion. 

Jacobs returned last week after several weeks out with the lingering effects of delayed concussion and had 26 disposals against the Suns, but is a late withdrawal for the third time in four weeks. 

The club says Jacobs will miss the game with further concussion symptoms and neck soreness.

Speaking on Channel Seven pre-game, coach Brad Scott said an incident from earlier in the season is still causing Jacobs issues.

"We've isolated it more to the neck. There was an incident, I think in round 11, so a long time ago … it's just referring into a few headaches and things like that," Scott said.

"Where there's any doubt with those sort of things we've just got to take him out. 

"It's frustrating for everyone that we've named him four times and he's played once in the last month, but we've just got to be ultra cautious."

Post-match, Scott said he doesn't hold major concerns for the midfielder.  

"I'm not because I see him day-in day-out and he looks good. It's a really hard one to explain because I'm a little bit miffed myself," he said.

"He seems OK and we're not playing games picking him every week. It appears he's right to go but again it's something doctors are a little bit nervous about understandably with anything that involves the head and neck.

"We've isolated it to more of a head problem than a neck problem. I don't know if one's better than the other, but it's frustrating for him, that's for sure."