ROSS Lyon hopes sending Hayden Ballantyne back to the WAFL will release the "pressure valve" on the Fremantle veteran after intense speculation about his form.

The Dockers have made six changes for Sunday's clash with Collingwood at the MCG as Lyon delivered on his promise to double down on the rebuild.

Despite star forward Michael Walters' wish for Ballantyne to remain in the line-up, the 30-year-old has been dropped after laying one tackle and kicking one goal in the past two losses to Sydney and North Melbourne. 

"He's working really hard. His output's high, as in running output, and effort is strong," Lyon said.  

"But in fairness, our football, I think our first six weeks was very strong and (we had) a fair bit of ball and entry, even against the Eagles we went right to the end.

"Then supply has been really quite difficult, and a young forward line around him and not that tall. 

"In some respects, this releases the pressure valve for him. 

"As much as he'd love to be playing, sometimes there's a relief when it's not quite going your way.

"They're only human, they would hear external criticism."

Lyon believed Ballantyne, out of contract at season's end, still has "plenty of good footy in him".

Experienced campaigners Michael Johnson and Danyle Pearce have also made way for youth, while recruit Brandon Matera has been dropped for the first time. 

"When you get challenged, it's how you respond, and we're confident that those guys, particularly experienced guys, have had great character and you're a product of your habits," Lyon said. 

"They'll be fine and we'll work with them. They want the team to win, they won't be wearing out their shoes trying to stop the team." 

After losing giant ruckman Aaron Sandilands to concussion, the Dockers have called in injury-ravaged Michael Apeness for just his eighth game in five seasons and mature-aged draftee Scott Jones for his debut. 

The duo face the tough task of combating red-hot Pies big man Brodie Grundy and 211cm sidekick Mason Cox. 

"He's (Grundy) an exceptional player," Lyon said. "He's probably the best ruckman in the competition at the minute. 

"Michael has basically been unavailable for five years, in a sense, and even this year he's just got back, so he's going to need some assistance." 

Lyon confirmed former Geelong forward Shane Kersten had been recalled to play in defence in his first game since round one. 

Speedy rookie Stefan Giro will debut and running backman Taylin Duman is set for his fifth game.

The Dockers, who sit in 13th spot with a 4-6 win-loss record, will have nine players under 25 games' experience against the Pies. 

Despite bumps along the way, Lyon said he has been invigorated by the challenge of leading the turnover of the squad and blooding new talent over the past two years.

"We're all in, and (Nat) Fyfe understands. It's drawn us closer together, and Lachie Neale, the leaders, because we know they're not going to be perfect but our job is to educate them," he said.

"There's some incredible things going on here, so that won't always be reflected on the scoreboard. 

"It's a slower burn, but one we're really enjoying."