The Sydney Swans will welcome back co-captain Kieren Jack for Saturday's clash with Richmond at the SCG.

But, in a shock omission, young gun Callum Mills will miss his second game of the season after being ruled out with injury.

Fortunately, coach John Longmire expects Mills to be sidelined for one week in what looks to be only a minor calf complaint.

"He was touch and go whether he'd be right to play," Longmire revealed in this week's Centrum Team Selection.

"In the end we've just decided not to take any risk."

In better selection news, Jack's return is a timely boost for the Swans who are coming off a close but strong win against finals-bound North Melbourne in Hobart.

He missed that game with an ankle injury suffered in the last training session of the week, bringing back memories of last year's season-ending ankle injury.

Longmire had his fingers crossed it was only a one-week injury and the coach got his wish.

Dean Towers (omitted) makes way for the co-captain while Harry Marsh will play his first game in over two months as the replacement for Mills.

Towers, Jordan Foote and Toby Nankervis have been named as emergencies.

Jack's welcomed return will add further depth to a midfield preparing to take on an opposing outfit featuring Dustin Martin and Trent Cotchin.

"It has been great to see him back up and about this week," Longmire said.

"He was able to run earlier in the week and then felt good after training today which was terrific."

Richmond has proven to be a bogey side of late.

Sydney hasn't beaten the Tigers since 2014 with the last three encounters going down to the wire, none closer than the last meeting when Richmond's Sam Lloyd kicked a goal after the siren to steal a one-point win in Round 8 earlier this season.

Longmire said his side needed to pay full respect to an opposition capable of matching it with the best in the competition.

"At their best they're a good side, and have some really good players," he added.

"We need to make sure we need to restrict the impact of those players and play good two-way footy.

"We left it up to luck (last time)."

To view the full squad, click here.