BRYCE Gibbs should be fit to start 2016 pre-season training on time after undergoing surgery to repair a torn left pectoral on Monday, according to leading sports medico Dr Peter Larkins.

Gibbs ruptured his pectoral in a tackle against Richmond on Friday night and Carlton announced on Monday afternoon that he was set to have season-ending surgery later that day. 

Larkins told AFL.com.au Gibbs' injury was part of a recent spike in pectoral tears in the AFL.

"Bryce was injured in a very similar fashion to the pectoral muscle tears we've seen Josh Gibson, James Frawley, Dale Morris and Joel Tippett suffer in recent seasons," Larkins said.

"The increased number of pectoral injuries in the AFL is probably due to a combination of the game's increased velocity and tackling intensity. 

"The expected recovery for these injuries is somewhere in the 10-14 week mark which means Bryce should be right to go for pre-season training."

Carlton also announced on Monday that Dennis Armfield would miss the next four weeks after breaking his right arm against Richmond. 

Armfield will have surgery to insert a plate into his right arm this week.

Larkins said Armfield had broken the ulna bone in his forearm, an injury that could sideline him for up to six weeks.

"If he has the surgery, four weeks would be an earlier return than usual. This sort of injury usually involves a six-week absence from footy," Larkins said. 

"Players usually return wearing some sort of guard or padding."

Larkins also said St Kilda captain Nick Riewoldt was in considerable doubt for Sunday's tribute match for his late sister Maddie after suffering a calf injury against Greater Western Sydney.

Madeleine Riewoldt, 26, died in February after a five-year battle with aplastic anaemia.

It was announced last month that the Saints' round 16 clash with Richmond would be named 'Maddie's Match' and serve as a fundraiser for the newly formed organisation Maddie Riewoldt's Vision, which aims to raise funding, research and awareness to fight bone-marrow conditions.

Larkins said Riewoldt left the ground with calf and mid-Achilles soreness during the final quarter of the Saints' 35-point loss to GWS on Sunday, and was awaiting scan results to learn the extent of his injury.

"Nick has had a history of left calf problems this season which caused him to miss matches," Larkins said.

"Because calf injuries are increasing in the AFL and tears result in significant time out, if a tear shows up on the scan Nick will be in considerable doubt for this week's game."

If Riewoldt misses Sunday's game, his and Maddie's cousin, Richmond spearhead Jack Riewoldt, should still play.

Star GWS midfielder Dylan Shiel was substituted out of the Giants' win over St Kilda after suffering a right knee injury in the second quarter and will miss up to 12 weeks due to surgery, the club announced late on Monday afternoon.

Larkins said Shiel had injured himself in a "fairly innocuous" incident.

Richmond announced last Saturday that Shane Edwards had suffered a hairline fracture in his right fibula in the win against Carlton and would miss two to three weeks.

But Larkins said Edwards could miss up to four weeks.

"The club is optimistic that Shane's fracture will heal quickly and won't require surgery, but the best-case scenario is probably a 3-4 match absence," he said.

Gold Coast spearhead Charlie Dixon was substituted out of the Suns' loss to the Western Bulldogs late in the first quarter after injuring his right ankle in the game's opening minute.

Larkins said it was a positive the injury was not to the left ankle that troubled Dixon earlier this year, but he still expected it would sideline the big Sun.

"It's a lateral ligament sprain. The Suns are getting scans to determine the extent of it, but if he's sore and can't train he's clearly going to be restricted this week and possibly for longer," Larkins said.

Larkins said Bulldogs midfielder Koby Stevens could play this Saturday against Geelong after suffering a bruised lung against the Suns.

"The Bulldogs were concerned about internal damage but he's escaped with a contusion, which is low-grade bleeding into the lung," he said.

"He was able to return to Melbourne with the rest of the team on Sunday morning and the Bulldogs are optimistic he may be right to play against Geelong.

"But Koby will still have to get through a training protocol this week and see how sore he is before he can play."

Larkins also said:

- Collingwood is awaiting further specialist opinions on the extent of the shoulder injury Tim Broomhead suffered against Port Adelaide. Broomhead is still experiencing pain in his shoulder and is likely to miss at least two weeks.

- Hawthorn defender Taylor Duryea seemed to suffer a subluxation or partial dislocation in his left shoulder when he completed a spoil in the win over Fremantle. Scans will determine whether he suffered more significant damage, but he is likely to spend at least some time on the sidelines. 

- Young Brisbane Lion Darcy Gardiner dislocated his shoulder in the first quarter against the Sydney Swans and will undergo season-ending reconstructive surgery.

- Port Adelaide ruckman Matt Lobbe was too stiff and sore to complete the game after landing on his back in the win over Collingwood, but should be available for Sunday's Showdown after intensive physiotherapy this week.

- Carlton defender Michael Jamison, Fremantle midfielder Clancee Pearce Bomber Alex Browne and young Roo Kayne Turner will all have to satisfy the AFL's concussion protocols to prove their fitness for round 16. All four players remain in doubt, but in a positive sign Browne had recovered pretty well from his significant concussion by the end of the game against Melbourne.