FREMANTLE coach Justin Longmuir expects two-time Brownlow medalist Nat Fyfe to return to the AFL before the mid-season bye after undergoing back surgery last month.

The 30-year-old Dockers skipper has not played this season after the March 26 surgery, which came after an off-season shoulder operation which impacted his pre-season.

Fremantle hadn't set a definitive timeframe on Fyfe's return after the back surgery, with the captain originally stating he hoped to be playing again six weeks after the operation, approximately at round eight.

Longmuir told reporters on Thursday that he expects Fyfe to be back prior to the Dockers' mid-season bye, scheduled for round 14.

"Probably a couple of weeks before the mid-season bye, around that time," Longmuir said.

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"It's hard to put it into timeframes for him. There's a bit of an unknown around the injury but he is progressing well and we expect him to keep progressing those loads."

Fyfe had hoped to return to running two weeks post-surgery and Longmuir revealed he hasn't been able to do anything on grass yet.

"We expect that to ramp up over the next couple of weeks," he said.

"It's all gone to plan so far. He's been able to run on the AlterG and get some run into his legs that way. We expect him to be able to keep progressing."

Fremantle, which is 3-1 this season, takes on Essendon on Sunday at Marvel Stadium.