AFL ladder-leaders Sydney will be without Charlie Curnow for their clash with North Melbourne after the high-profile spearhead was ruled out with an abdominal injury.
The Swans are hopeful one week on the sidelines will be enough for Curnow to recover, eyeing a huge home clash with Collingwood in round 10.
But the key off-season acquisition and in-form defender Jai Serong (hamstring tightness) will both be absent against the Kangaroos at Marvel Stadium on Saturday.
"They were sore at the start of the week and we've worked our way through the best way to manage them, and they're injured and not available," Swans coach Dean Cox said.
"They'll both be very short-term. That's what we know. If it's just this week, hopefully that's the case, but we expect them hopefully back next week."
Cox said ruck star Brodie Grundy had pulled up "really well" this week after battling soreness and will lead the line against North Melbourne.
Hayden McLean replaces Curnow and will provide support for Grundy opposed to physical Kangaroos ruck Tristan Xerri, while Harry Cunningham has also been called up.
George Wardlaw returns for North after a week out through illness.
Essendon have lost patience with Ben McKay, dropping the out-of-form defender for their clash with GWS at Engie Stadium, while Darcy Parish and Mason Redman are among five inclusions.
The Giants will be without key forward Jesse Hogan, who has a hip injury, as well as Ryan Angwin (concussion), Leek Aleer and Xavier O'Halloran (both ankle).
Toby McMullin, Max Gruzewski and Oliver Hannaford all return, while Jake Riccardi replaces Hogan, who faces an uncertain period on the sidelines.
"It's just like a really deep cork in his hip that just doesn't free up, so we need to manage that symptomatically," GWS coach Adam Kingsley said.
"I don't think it'll be a long-term injury, but I have been guilty of saying that in the past.
"We'll just manage his symptoms and hopefully he's back as soon as possible."
Collingwood ruckman Darcy Cameron is set to play against Geelong at the MCG on Saturday night after overcoming an ankle injury.
In further boosts for the Magpies, Jeremy Howe and Beau McCreery will return alongside Scott Pendlebury, who is set to equal retired North Melbourne champion Brent Harvey's AFL record of 432 games.
The Cats have recalled Rhys Stanley in place of managed ruck Mitch Edwards.
Gold Coast will be without Brownlow Medal winner Matt Rowell (ankle) for their clash with St Kilda in Darwin on Saturday night.
Saints forward Liam Ryan (corked hip) will miss a second consecutive game, while Darcy Wilson replaces Dan Butler (hamstring).
On Sunday, Tim Taranto is back for Richmond against Adelaide, who lost former captain Taylor Walker (hamstring) but regain skipper Jordan Dawson.
