Aaron Sandilands is recovering after suffering fractured ribs and a collapsed lung against West Coast on Saturday's night.

The ruckman will be discharged from hospital in the next few days but could miss up to six weeks.

"Our medical advice is that the surgery went well and that Aaron will spend a few days in hospital resting up," Fremantle General Manager of Football Operations Chris Bond said.

"Aaron will then go through a recovery phase after which our medical staff will be in a position to confirm how many weeks he is expected to miss before being available to play again."

Meanwhile Dockers’ captain David Mundy is expected to miss another week with a calf strain.

Jon Griffin is set to replace Sandilands against North after accumulating a game-high 36 hit-outs and 11 touches against the West Coast-affiliated East Perth in the WAFL. Zac Clarke is still nursing a knee injury he suffered in round one against the Western Bulldogs, while fellow tall Jack Hannath is also available.

Hayden Crozier could receive a call up after three goals, 30 disposals and eight tackles while forward Matt Taberner booted three goals from his 13 possessions.