HAWTHORN's injury-hit defence has suffered another big blow with Brian Lake set to miss at least four weeks with a medial ligament strain, leading sports medico Dr Peter Larkins says.

Larkins also told AFL.com.au that Lake's teammate Paul Puopolo (hamstring) was likely to miss two weeks and first-year Collingwood tall Darcy Moore (hamstring) at least three to four weeks, with Robbie Gray (calf), Jake Stringer (hamstring), Luke Shuey (ankle), Jack Martin (ankle) and Brett Deledio (calf) among those in doubt for round five.

Lake was substituted out of the Hawks' loss to Port Adelaide on Saturday night after injuring his left knee in a jostle for position with Jay Schulz in the first quarter. 

The two-time premiership full-back's injury comes at a bad time for the reigning premier with fellow key defenders James Frawley (pectoral) and Matt Spangher (hamstring) about a month away from resuming, and North Melbourne talls Drew Petrie, Jarrad Waite and Ben Brown awaiting the Hawthorn defence on Saturday night. 

But Larkins said Lake had probably dodged a high-grade medial ligament strain like Geelong's Jimmy Bartel suffered in round three.

"I think the scans will reveal it's in that medium-level severity rather than the worst one, like Jimmy Bartel's, that needs surgery," Larkins said. 

"I expect it's probably going to be four weeks at best; sometimes these injuries drag out to six weeks, but players can get back with physio and strapping on the knee. 

"It was a good sign that his foot was able to slip clear of the grass, so he didn't get stuck." 

Puopolo suffered his injury in the third quarter of the Hawks' loss to Port and did not come back on to the ground.

"It was an interesting one, it was everything from a quad to a corkie to a hamstring," Larkins said.

"Being a sprinter and being as fast as he is, it looks more like it's in the hamstring area at this stage and I would expect he's going to be missing for a couple of weeks."

Larkins said Moore had suffered "a reasonable severity" hamstring strain playing for Collingwood's VFL team on Sunday. 

"Scans will reveal if it's anything more severe than that but I'm expecting him to be out for at least three to four weeks," he said. 

"The scans will also reveal if his recovery is going to involve more than physiotherapy but being a younger player and being a higher-grade injury, normally you're looking at that four-to-six-week category just to get that risk of reoccurrence out of the way."

Shuey was substituted out of West Coast's victory over the Brisbane Lions in the third quarter, but Larkins said the Eagles midfielder remained a chance to play against Greater Western Sydney on Saturday night.

"Shuey was pretty sore at the end of the match. He landed awkwardly and he's got a history with the same ankle which always adds to the recovery," Larkins said.

"West Coast were optimistic he would come along because ankles get a lot of physio and can be strapped up. 

"But just on the back of the fact that he's had previous ligament trouble you would think Shuey is going to be pretty limited at training this week, so he'll be touch and go for this weekend." 

Western Bulldogs forward Jake Stringer starred against Adelaide on Sunday with six goals but was substituted from the game late in the third quarter.

Larkins said Stringer had avoided a hamstring tear, but would have to overcome tightness and soreness in the muscle to play against the Sydney Swans on Saturday.

"There's a reasonable chance that with a light training week he might be able to play next week but it will be touch and go," he said. 

Larkins also said:

- Port star Robbie Gray missed the win over the Hawks with a small calf strain that could require another week's rest, putting him in doubt for Sunday's Showdown against Adelaide.

- Lachie Henderson was struggling with calf soreness by the end of Carlton's win over St Kilda in Wellington on Saturday but with treatment this week could be fit for the Blues' clash with Collingwood on Friday night.

- Fellow Blues Chris Judd (hamstring) and Troy Menzel (calf) should return to training this week in a bid to prove their fitness for Friday night's clash.

- Bomber Paul Chapman (corked left knee) is likely to be fit to take on St Kilda on Sunday, but Saints stars Nick Riewoldt (calf) and Leigh Montagna (knee bone bruising) might still be another week away from returning.

- Gold Coast's Jack Martin (medium-level ankle injury) could miss the Suns' clash with the Brisbane Lions this Saturday.

- Swan Isaac Heeney (ankle) should be fit to play against the Bulldogs on Saturday.