FREMANTLE will regain key position players Luke McPharlin and Antoni Grover for this week's clash with Geelong but Des Headland (quad) and Hayden Ballantyne (back) face a race against the clock.

Headland and Ballantyne will both be tested at Thursday's main training session, while the versatile Michael Johnson (ankle) is still two weeks away.

Given the magnitude of this week's task, coach Mark Harvey said he would need to know the make-up of his side as soon as possible and couldn't afford to give players until the last minute to prove their fitness.

"I don't think you particularly want to be mucking around when you play Geelong too much with selection, so we'll need to let our players know who they're playing on specifically," Harvey said from Fremantle Oval on Wednesday.

Ballantyne, 21, is yet to play an AFL game after being selected by Fremantle at No. 21 at the 2008 NAB AFL Draft.

The small forward was a late withdrawal from the side that lost to Port Adelaide in round 11 and Harvey said if he didn't play this week, he would play next week.

"We think he's up for playing AFL, but we'll be guided by our fitness and strength guys," Harvey said when asked if Ballantyne would need a run in the WAFL before making his debut.

"He's had a spasm and it's taken a bit longer [than expected to recover].

"It's a fine line all of this. You don't want to be breaking him down at this stage."

In better news for the injury-hit club, tall forward Adam Campbell, who was concussed early against Port Adelaide, has recovered and will be considered to hold his place.

Second-year player Chris Mayne (stress fractures) is also progressing and will return to the WAFL in the next fortnight.

Harvey said he was looking forward to eventually having a host of players to choose from, especially given some challenging fixtures in the second half of the season.

"What you like to see is how your young players pit themselves against these sides," Harvey said.

"It can bring the best out of your group and I'd like to think that'll happen on the weekend.

"Naturally we'd like to have our full complement playing these sides to get a really good judgement on our list, but we're probably not going to have that for another three weeks."