NORTH Melbourne will enter Saturday's all-important clash against ladder leader Hawthorn with forward Ben Brown and defender Scott Thompson under serious injury clouds.

Brown hobbled off with a left knee concern early in the second quarter against the Western Bulldogs, while Thompson was forced off in the final term with a groin issue and spent the rest of the match receiving treatment.

Brown, who leads the club's goalkicking tally with 36 majors, leapt for a mark and landed on his already strapped left knee in a seemingly innocuous incident. 

The 23-year-old came off the ground minutes later and was assessed by the club's medicos, before heading to the rooms for a further check-up and emerging with his knee strapped in ice.

Brown's setback comes just days after forward Jarrad Waite had arthroscopic surgery on his lingering right hip complaint, with fellow tall Mason Wood also sidelined for an extended period following left knee surgery last month.

Hawthorn has concerns of its own ahead of its clash against the Kangaroos after defender Ben Stratton suffered a left pectoral muscle injury as he jumped for a mark on the wing in the second quarter against Melbourne.

The 27-year-old appeared restricted in his arm movement and did not return after half-time following the non-contact injury.

St Kilda midfielder Luke Dunstan is likely to need surgery to repair the left shoulder he dislocated midway through the final quarter against Carlton while attempting to tackle Blue Ed Curnow. 

The 21-year-old was in obvious pain as he walked off the ground cradling his arm, and later emerged in a sling with his shoulder back in its correct position.

Saints coach Alan Richardson said Dunstan would most likely require surgery, with confirmation to be known following the results of scans.

Dunstan had arthroscopic stabilisation surgery on his other shoulder towards the end of the 2014 season.

Essendon captain Brendon Goddard strained his groin midway through the opening term against Geelong and took no further part in the match.

The 31-year-old felt a sharp pain as he took possession uncontested in the back pocket and despite the injury, was forced to kick, turning the ball over to Cat Mark Blicavs with a short pass.

Western Bulldogs midfielder Clay Smith was left dazed after his head hit the turf in a chase-down tackle from Kangaroo Aaron Mullett. 

Smith came off the ground soon after the first-quarter incident and did not return after failing a concussion test.

The Bulldogs have a lengthy injury list, with Tom Liberatore (ankle), Jack Macrae (hamstring), Mitch Wallis (broken leg) and Jack Redpath (knee reconstruction) succumbing to injury over the past fortnight.

Collingwood skipper Scott Pendlebury hobbled off after rolling his left ankle in a final-quarter contest with Brodie Grundy and Richmond's Sam Lloyd, where Grundy seemed to inadvertently bump his teammate.

Pendlebury headed straight into the rooms for further observation and tried to perform some run-throughs along the boundary line a few minutes later, but was hampered by an obvious limp and did not return.

Gold Coast ruckman Tom Nicholls went down to the rooms at quarter-time with a posterior cruciate ligament issue in his left knee and is unlikely to be fully fit to take on Essendon on Sunday.

The 24-year-old returned in the second term with his leg re-strapped but struggled to have any major impact, finishing the first half on an exercise bike and battling through the second half with a pronounced limp. 

In other injury concerns at the weekend:

- Cat Daniel Menzel experienced groin tightness in the third quarter against Essendon and the club opted not to risk the injury-prone forward for the rest of the match.

- Bomber Courtenay Dempsey came off the ground early against Geelong with a left hamstring complaint and returned after getting re-strapped.

- Saint Nathan Wright received a knee to his back from Blue Kade Simpson in a contest before half-time. Wright sat out most of the second half, only to courageously return late in the game when teammate Luke Dunstan dislocated his shoulder.

- Sun Alex Sexton could barely run late in the second quarter against GWS with both a corked left quad and hamstring tightness. He battled through but his night ended late in the third term with ice strapped around his upper left leg.

- Crow Paul Seedsman suffered a corked buttock in the first quarter against the Brisbane Lions and experienced referred pain in his lower back. The 24-year-old sat out the rest of the game after receiving plenty of treatment.

- Demon Bernie Vince needed attention for a cut he receiving to the bridge of his nose from James Sicily, as the Hawk attempted to spoil in a second-quarter marking contest.

- Swan Gary Rohan suffered a corked hip/buttock from a Charlie Dixon knee while jumping for a mark early in the first quarter against Port Adelaide. The 25-year-old returned to the field after a spell on the bench.

- Magpie Mason Cox received a massage through his neck and heavily strapped right shoulder in the first term against Richmond soon after falling to ground in a one-on-one marking contest. He returned and saw out the game. 

- Giant Jeremy Cameron was assessed in the third quarter for an apparent groin complaint but got through the match with ease.