FREMANTLE utility Matt de Boer is set to miss the next four to six games after injuring his knee at training on Wednesday.
De Boer is in a brace after injuring the medial ligament in his left knee.
The 24-year-old hasn't missed a game since round 12, 2012, but will be sidelined for games against the Bulldogs, Crows, Tigers and Lions, before a possible return against the Eagles on June 28.
The Dockers sit in seventh spot after losing four of their opening nine games.
But, with their next nine games against opponents who sit no higher than ninth, last year's grand finalists are expected to make a charge up the table, starting with Sunday's clash with the Bulldogs at Etihad Stadium.
Meanwhile, Fremantle forward Scott Gumbleton could be back on the footy field within three weeks, but he'll have to overcome the "daily grind" if he is to win a spot in the Dockers' line-up in the second half of the AFL season.
Gumbleton was plagued by back and hamstring issues during his seven seasons at Essendon, but Fremantle took the punt on the 25-year-old at the end of last year in a bid to ease the burden on spearhead Matthew Pavlich.
However, the plan to turn Pavlich and Gumbleton into Fremantle's twin towers suffered an early setback when the ex-Bomber tore his hamstring during the pre-season.
Gumbleton is back in full training and will resume in the WAFL for Peel Thunder's clash with Swan Districts on June 14.
However, coach Ross Lyon said a fairytale Dockers debut would have to be earned the hard way by Gumbleton.
"He's showing great resilience to persist and get himself back," Lyon said.
"But before we start extrapolating out and making assumptions about future performance, he really needs to get through his full rehab, bang three weeks in at Peel and put his hand up for selection.
"That's the harsh reality of it.
"The romance and sitting there and assuming and painting rosy pictures doesn't occur at our end. It's a daily grind that you have got to deliver on and get through."
Gumbleton is holding out hope of being able to force his way into the Dockers' forward line.
"I'd like to be able to be a presence down there and provide a contest and, hopefully, help out the key forwards and the little fellas crumbing around," Gumbleton told the Fremantle website.
