Fremantle made an immediate exit from the NAB Cup after experimenting with new and young players against West Coast and Hawthorn at Patersons Stadium 10 days ago.
Mitchell said the approach would continue this week and the club wouldn't look to field its best line-up until the final two practice matches of the pre-season.
"Probably the last practice match especially, and probably a half a game of the practice match before," Mitchell said from Fremantle Oval on Wednesday.
"What we're trying to do is get the team together for the first round.
"I think particularly for the new players, you put them in a few different situations and see how they go. Sometimes you get a bit of a surprise.
"There was a bit of that last week. We tried (Justin) Bollenhagen down back for a little bit and he probably hasn't played there much.
"I think that'll continue this week and maybe a bit into next week, and then you'd be probably looking to settle the side down."
After pushing through to the second week of the finals last year, Fremantle was a surprise loser in the first round of NAB Cup matches against young Hawthorn and West Coast sides.
However Mitchell said the club was unconcerned by the early exit.
"Last week was our first hit-out - that's not an excuse, it's a fact," he said, with Fremantle choosing not to play an intra-club match in the lead up to the pre-season competition.
"We probably didn't play as well as we wanted to, but in the end it's all about round one.
"It's about the season, it's about the 24 weeks. It's not about the first game of the pre-season.
"We can look back to last week or look forward to what the season is, which is the main show."
While Fremantle will continue experimenting with new players - including mature-age recruits Tendai Mzungu, Nick Lower and former Adelaide ruckman Jon Griffin - Mitchell said the club would make sure it selects enough senior players "to help the younger guys".
Mitchell expected Nat Fyfe, who missed round one of the NAB Cup with illness, would be "around the mark" when the side to travel to South Australia's Thebarton Oval was selected on Wednesday afternoon.
"He's put on a bit of weight and he's run really well," the midfield coach said.
"Early in the year in the time trial I think he came second or third - he's lifted in that area.
"He's only a younger player we hope improves again. He started the year pretty well last year, so hopefully he can improve again this year for us."
Senior coach Mark Harvey has suggested key midfielder David Mundy and youngsters Dylan Roberton and Michael Walters could also be ready for their first pre-season hit outs.
Hayden Ballantyne, who returned to full training on Monday, will continue to be held back after a long rehabilitation from stress fractures in his right foot.
