NORTH Melbourne has been dealt a blow with key forward Ben Brown suffering a knee injury in the second quarter of Saturday night's clash against the Western Bulldogs.

Brown hobbled from the field in the second term, briefly went down to the rooms and emerged only to have ice applied on the interchange bench, signalling his night was done.

Brown's injury could prove disastrous for the Roos' run home with Jarrad Waite (hip) and Mason Wood (knee) both sidelined.

The 200cm big man is North's leading goalkicker with 36 majors this season and has become the club's focal point in attack.

Meanwhile, the Bulldogs are also down a player with Clay Smith concussed in a tackle by Aaron Mullett in the first term.

Smith's head appeared to be driven into the turf in the momentum of the tackle and he is also out of the match after sitting on the bench in a tracksuit during the opening half.

Brown and Smith's injuries continue a horror run of luck for their respective teams, who are both dealing with extensive injury lists on the run towards September.

Waite has undergone hip surgery and is doubtful to return before the first week of finals, while Dogs stars Tom Liberatore (ankle) and Jack Macrae (hamstring) are also pushing for a finals return after injuries in last week's loss to Geelong.

Clay Smith with the tracksuit on after a first-quarter concussion. Picture: AFL Photos