Aussie great's brutal take on struggling Handscomb

With AAP

Former Aussie Test opener Michael Slater has provided a blunt assessment of Peter Handscomb's form, saying the under-fire batsman is "gone in the head".

Handscomb is scrapping with in-form all-rounder Mitchell Marsh over the final spot in Steve Smith's XI that will face England in the WACA clash that starts on Thursday.

The 26-year-old Victorian has passed 50 in one of his nine first-class knocks since the start of the season, with speculation building he will be dropped in favour of Marsh.

A flat pitch - which is the widespread expectation in Perth - is likely to result in selectors wanting an allrounder in the team.

Slater has now joined a chorus of experts pushing for that result.

Handscomb has struggled to find form so far this series. Pic: Getty

"My personal feeling is that he’s gone in the head," Slater told Sky Sports Radio.

"All the pulling apart of his technique is valid in the commentary box and they’re doing the same on the radio, it all gets back to the player.

"They can’t avoid it. If they don’t hear it their mum or dad or their brother or sister hears it or they’re friend says, ‘Gee they’re ripping into you, I don’t know why mate, you’ve had a couple of bad innings’.

"And he says, ‘It doesn’t bother me’. But it’s in his head and as soon as you doubt yourself, and I think he’s doubting himself, then that’s enough for me. They’ve got the form player (Marsh) there."

Shane Warne has also entered Australia's selection debate that appears to be swinging in Mitch Marsh's favour ahead of the third Ashes Test.

The legendary leg-spinner posted on Twitter that "Australia would like to keep a winning team together, but unfortunately Handscomb needs to go back to Shield cricket urgently and sort his technique out".

The Sheffield Shield is however on its mid-season hiatus. Handscomb would instead return to Big Bash League club Melbourne Stars if he is axed.

A handful of Twenty20 matches would ensure Handscomb finds it hard to convince selectors he warrants a recall for the MCG or SCG Tests against England.

Australia landed in Perth on Sunday and then trained at the WACA on Monday. Handscomb was stationed at first slip during fielding practice, while he had an extended hit and was one of the last batsmen to leave the nets.

National selector Mark Waugh backed Handscomb to find form last week, calling the Victorian "mentally strong".

Former captains Michael Clarke and Allan Border both suggested last week they would stick with an unchanged XI.