MICHAEL Johnson joined a growing Fremantle rehab group at training on Monday, just over three weeks out from the Dockers' first NAB Challenge match.

Johnson joined Nat Fyfe, Harley Bennell, Zac Clarke, Alex Pearce, Michael Apeness, Brady Grey, Harley Balic and Shane Yarran in the rehab group that trained following the Dockers' main session at Fremantle Oval.

Johnson has trained with the main group for most of the summer but only completed some running with the rehab group on Monday. He has battled back and hamstring injuries in the past two seasons but did not appear restricted while running.

Fyfe continues to move well as he manages his return from a leg fracture and a back issue.

Bennell remains on light duties, having trained away from the main group since Christmas, only performing some low-intensity running and kicking on Monday.

However, teammate Lachie Neale said the Dockers weren't concerned that Bennell had not been able to train with the midfield group so far this summer.

"All those rehab guys have sat in all the meetings when we've gone through most of the game-plan," Neale said.

"(Harley) is really across it and he's working hard with the coaches upstairs getting a grip on the game-plan and the way we want to play.

"I'm sure once he steps in he'll be ready to go, and I'm sure in the rehab group they sort of practice what we want to do as well when they get a chance to kick and do a bit of footy stuff.

"We've still got two months until the season, so we're not really worried about that at the moment and he'll join in when he's ready."

The Dockers' first match of the premiership season is against the Western Bulldogs on March 27 but they play their first NAB Challenge match on February 19.

All nine men the rehab group participated in some running on Monday, with Pearce and Apeness the most restricted in terms of intensity.

Pearce battled shin soreness last September and has also reportedly experienced some groin soreness this summer, while Apeness is still working his way through ongoing knee issues.

Clarke and Grey are closing in on returns to the main group while 2015 draftees Balic (wrist) and Yarran (knee) are being managed through their first pre-seasons.

Neale said the main group was building up towards full match practice in the coming weeks.

"We've started to do some full-ground drills over the last couple of weeks," Neale said.

"I'm sure over the next couple of weeks that will build up to extended minutes."