FREMANTLE will continue to hold back Stephen Hill and Hayden Ballantyne from pre-season matches, but coach Mark Harvey is confident the dynamic pair will be ready to fire in round one of the season proper.

Fremantle will have this weekend off after being eliminated from the NAB Cup by West Coast and Hawthorn, and the club expects to travel to Adelaide next Friday night for a NAB Challenge fixture.

Hill and Ballantyne will not be considered for that match and are both two to three weeks away from playing.

However, Harvey said one or two practice matches would be enough to prime the pair ahead of the club's season opener against the Brisbane Lions at the Gabba on March 26.

"Some guys come up a lot quicker than other guys - they can have a limited preparation and they only need a couple of games to reach their full match fitness," Harvey said from Fremantle's Telstra community camp in Kalgoorlie.

"[Hill] is one of those, so we're just not pushing him at the moment.

"We'd probably like [Ballantyne] to have two or three weeks under his belt of training before he moves into a game."

Ballantyne will join full training next week after a lingering foot injury was managed through the pre-season, while Hill has been on a modified training program since returning from the Christmas break.

Harvey said recent leadership group addition Matt de Boer was also one to two weeks away from playing as he recovers from a hamstring complaint. 

Fremantle has suffered serious pre-season injuries to Anthony Morabito (knee) and Roger Hayden (foot), while Garrick Ibbotson (ankle) and Joel Houghton (broken arm) are also sidelined.

"We've just got to make sure we can get as many players to round one as we need," Harvey said. "As we know, it's crunch time and everyone's trying to get off to a good start."

Harvey said up to four players would play their first pre-season matches next week, while he would use the next phase of the club's preparation to gain a better understanding of the new interchange rule. 

However, the coach was yet to be convinced that the substitute system would reduce injuries.

"We're just going to ask players to play on the ground for longer periods … we're about to find out whether that might increase the injury toll or not," he said.

"If they're asked to stay on the ground longer - and we know how taxing the season is - we'll be watching it carefully.

"[The NAB Challenge] gives us a good chance to get back to the format that's going to be used in season. I'd say it'd be another game where we're trying some of our younger players.  

"(David) Mundy might be nearly ready to play, Michael Walters, Dylan Roberton, those sorts of guys we might look at. There'll be three or four new players introduced."

Stephen Hill is a $277,000 midfielder in the Toyota AFL Dream Team competition