NORTH Melbourne forward Mason Wood looks to have escaped serious damage to his right knee but has been ruled out of Saturday's vital clash against Port Adelaide and could yet require surgery on his medial ligament.

Midfielder Farren Ray will also miss the Port game with a hamstring injury that's expected to sideline him for four to six weeks, but Majak Daw (ankle) could be available.

And out-of-favour forward Aaron Black's year could be over, with North to determine soon whether he requires season-ending ankle surgery or can attempt a return late in the season.

Wood was injured when he tackled Will Schofield in the third quarter of North's loss at Domain Stadium on Sunday, with the West Coast defender falling across his right leg.

North football director Geoff Walsh confirmed on Monday Wood had suffered a medial ligament injury in the incident.

"Our medical team's first thoughts are there is no serious damage for Mason, however he will meet with a specialist later this week to see if he requires any surgery," Walsh told NMFC.com.au.

Ray injured his hamstring during the second quarter of the Eagles loss and did not return to the ground.

Earlier on Sunday, North's poor run of injury continued in the VFL when Daw and first-year defender Mitchell Hibberd went down in Werribee's loss to Port Melbourne.

Daw injured his ankle when he landed on teammate Braydon Preuss' foot in the first quarter, while Hibberd injured his left knee when trying to change direction in the second term.

"Majak has pulled up really well today after rolling his ankle early in yesterday's game and he could be in contention to play this weekend, depending on how he recovers throughout week," Walsh said.

Hibberd had his left knee reconstructed in 2013, but North hopes his latest injury will only sideline him for a month. 

"There were initial fears that Mitch had suffered a serious, long-term knee injury, however scans have cleared him of any structural damage," Walsh said.

"He has a displacement of the knee cap, a similar injury to what he had earlier in the year. A timeline on his return is still to be confirmed, but we hope he will only spend around a month on the sidelines."

Black has missed Werribee's past two games after a heavy collision against Coburg left him concussed.

Walsh said Black had also injured his ankle in the collision and would be sidelined indefinitely.

"When 'Blacky' was involved in a heavy collision playing for Werribee a couple of weeks ago, he landed awkwardly on his ankle as he fell to the ground," Walsh said.

"We're now just waiting to see how that ankle settles over the next week or so before we decide if he goes under the knife or if he can get back and play in the latter stages of this year."