Sydney ruckman Shane Mumford will miss Sunday's clash against North Melbourne with a back injury.
The Swans' big man pulled up sore after the club's training session on Friday, prompting his omission.
“Shane’s back flared up again today,” Sydney coach John Longmire said.
“It’s a bit similar to what happened two weeks ago, and it is an issue that we’ve got to get right."
Mumford was a late withdrawal from his team's clash against Fremantle in round two, but was influential in the 22-point win over Port Adelaide with 40 hit-outs.
“We thought he was fantastic last week on ball for us, and he pulled up immediately after the game pretty well but then the longer the week has gone on, the worse his back has gotten," Longmire added.
“Our medical staff are doing everything in their power to make sure it’s not an ongoing issue so that’s what they’re working on at the moment."
Mumford joins Adam Goodes on the sidelines, after the two-time Brownlow Medalist was suspended for a week.
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