FORWARD Jack Gunston is very unlikely to overcome an ankle injury and play in Hawthorn’s semi-final clash against Adelaide on Friday night, leading sports medico Dr Peter Larkins says.

In more grim news for Hawks fans, Larkins says Gunston is also in doubt for the following week's preliminary final against Fremantle in Perth should the Hawks win.

Gunston injured his right ankle in awkward fashion in Friday night's qualifying final against West Coast.

"Hawthorn has conceded it's a big risk to play him this early because of the syndesmosis ankle injury he went through," Larkins told AFL.com.au.

"Because it's a Friday night game they're likely to give him the week off in the hope he comes up fairly well the following week.

"He's a chance (against the Crows) but he'd be a huge liability this week. They won’t risk him if there’s any concern by Thursday. Another week of physio will give him a better chance in the preliminary final week."

However Isaac Smith, who injured the medial ligament in his knee against Carlton in round 23, is a certain starter despite looking less than 100 per cent against the Eagles.

"It was a surprise that he did play. He wasn't expected to come up," Larkins said.

"My understanding is that it didn't limit him and I don't think there's any doubt that he'll play with the strapping on the knee."

The Sydney Swans will almost certainly not have star midfielders Kieren Jack (medial ligament knee strain) and Luke Parker (broken fibula) available for their semi-final against North Melbourne at ANZ Stadium.

But in good news for the Swans, they are both tracking ahead of schedule.

"[Kieren Jack] had a high-grade medial ligament sprain. He'd normally be missing at least three weeks but at finals time they might be able to compromise on that," Larkins said.

"He'll be touch and go to play (against the Roos) – I'm not expecting him to get up this week."

Swans coach John Longmire joked Parker was doing "cartwheels" by his office trying to convince him he is ready to play and Larkins said he may be available for the preliminary final against the Eagles, if the Swans beat the Roos.

"The best case scenario they thought would be 5-6 weeks to get him back – that's still early for someone who has a broken fibula with a plate in his leg," Larkins said.

"The five-week mark would be ahead of schedule to come back but he's probably in the mix."

However Larkins is of the understanding that All Australian defender Nick Smith could return for the game against the Kangaroos.

"The Swans will put him through the normal hamstring testing but he's done as expected with the games that he's missed," Larkins said.

"It was always going to be two or three weeks so it's not unreasonable they're considering playing him.

"If he gets through their testing they're likely to bring him in."

North Melbourne defender Jamie Macmillan injured his left ankle late in Sunday's elimination final against Richmond but Larkins has declared him ready to go against the Swans.

"Macmillan was off the ground in the last quarter and was having a lot of trouble putting weight on it," Larkins said.

"They were able to get really good strapping on it. They'll be able to get further recovery with ice and physio during the week.

"He'll need some pain relief and strapping to play but he'll be available."

Larkins also said:

- Star West Coast midfielder Matt Priddis (thigh) is a certain starter for the club's preliminary final clash against the Sydney Swans or North Melbourne.

- Fremantle defender Luke McPharlin, who was a late withdrawal with calf tightness against the Swans, would also be ready for his side's preliminary final against Hawthorn or Adelaide.

- Jeremy McGovern would benefit from the week off after spending at least 18 minutes off the ground receiving treatment for his injured AC joint (shoulder) against the Hawks.

- Chris Masten (hamstring) is a strong chance to return for the Eagles' preliminary final clash in Perth in a fortnight's time

- Dockers backman Cameron Sutcliffe (dislocated shoulder) would continue to manage his injury through the finals but is at risk of further instability. He will likely have post-season surgery.