Sydney ruckman Shane Mumford will miss another three to four AFL matches after having an operation to overcome a back infection.

The Swans’ No.1 ruckman has played just two games this season, missing the round two clash with Fremantle and last weekend’s meeting with North Melbourne with back pain.

After this week being diagnosed with an infection, antibiotics were tried but had no effect.

“The infection in Shane’s back did not respond to treatment as we had hoped, so he underwent a simple procedure to remove it,” Swans football manager Dean Moore said.

“He is recovering well and we expect him to resume training in around seven days, with a view to have him available for selection in the next three to four weeks.”

Unbeaten Sydney meet Hawthorn in Launceston on Sunday, when Mark Seaby will again lead the ruck.