VETERAN Sydney Swans defender Ted Richards failed to train on Monday as he recovers from concussion and remains only an outside chance of playing in Friday night's clash with North Melbourne at the SCG.

Richards landed heavily after taking a courageous mark in the first quarter of the Swans' 14-point win over Hawthorn last Friday night and played no further part in the game.

It was the 32-year-old's second game back from a broken cheekbone he suffered against Essendon in round five. 

Richards missed one game last year after he was concussed following a sling tackle from Port Adelaide's Jay Schulz in round 14.

Coach John Longmire refused to rule out the 2012 premiership defender but said Richards' availability would be up to the club's medical staff. 

"We'll wait and see how the week progresses," Longmire said.

"We'll see how he goes on Wednesday before we make any decisions, but obviously we're not going to take any risks.

"It gets down to what the doctor says, in conjunction with Teddy."

The potential loss of Richards would leave key defensive duties to Heath Grundy, Dane Rampe and Jeremy Laidler, but  could also lead to a shock recall for versatile forward Sam Reid, who hasn't been seen since he badly injured his hamstring in the Swans' qualifying final loss to Fremantle last year.

Reid progressed well in his rehabilitation program during pre-season training but has struggled with hamstring and calf issues since the Swans' first intra-club game in February.

The 24-year-old hasn't played a game at any level this year but has trained strongly over the past month.

The Swans have no set strategy when it comes to returning players, with co-captain Jarrad McVeigh (knee) coming straight into the senior side after an interrupted pre-season, while Ben McGlynn (hamstring) and Gary Rohan (hamstring) were both forced to work their way back through the NEAFL.

Longmire hinted that Reid's solid preparation could work in his favour when it came to selecting this week's 22 to face the Kangaroos.

"He'll certainly play at some level," Longmire said.

"The likelihood is he'll come back through the reserves and get some game time there, but our condition and medical staff are really confident that he can play big minutes this week based upon what he's done over the last six weeks.

"He's a very important player for us.

"We'd like him back in the senior team as quick as we can, whether that's this week or not we'll have to have that discussion."

While Longmire said that in an ideal world Reid would play at centre half-forward when fully fit, he has been used in defence in the past and could play a role there against the ladder leaders.

North's trio of dangerous talls in attack have been difficult for opposition team's to counter this season, with Jarrad Waite, Drew Petrie and Ben Brown all firing at different stages.

The three Kangaroos have kicked 57 goals between them in 2016.

"They've got a very good marking forward line, North Melbourne," Longmire said.

"They've got some terrific options in that front half but primarily they're marking targets, and they're not only marking players but they're good pressure players as well.

"They're a very good team, so we have to restrict the times it gets in there to give our defenders the best possible chance."