Tim Paine rubbishes England great's ominous Steve Smith claims

Steve Smith has taken his first steps toward a Test return, walking laps of Headingley as debate swirls over whether the incredible batsman will have mental demons whenever he is cleared to bat again.

Australia are confident they can retain the Ashes in Leeds without Smith, who has been officially ruled out of the third Test because of concussion.

The former skipper cut a desolate figure at training on Tuesday, when team doctor Richard Saw declared him unavailable for selection.

Smith was more upbeat and active on Wednesday, when he prowled the boundary alongside Dr Saw while some teammates hit the nets.

It may not seem like much - and was a far cry from facing a spell of short stuff from Archer - but the milestone was significant.

Provided he pulls up ok from the low-intensity activity, Smith will soon gradually step things up with more vigorous exercise then basic cricket drills.

The 30-year-old will have to face fast bowlers in the nets before he is cleared to play, which the tourists hope will happen in time for next week's tour match against Derbyshire.

"There's a strong medical process in place. Steve has to tick a lot of boxes to make sure he's ready to go, that our medical staff are comfortable with him playing," Tim Paine said.

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Paine rubbished the notion, put forward by former England captain Nasser Hussain, that Smith's stunning form could be affected by his nasty scare.

"Steve Smith is the best player in the world. He will come back next Test or the tour game and we're expecting it will be the same old Steve," Paine said.

"He's a high-quality player and he will adapt, as he always has."

Counterpart Joe Root suggested it was hard to tell what impact the blow will have on Australia's talismanic run-glutton.

"I've never had a blow as serious as that, so hard to comment," Root said.

"The thing that hurts the most is your ego. You're stood out there in front of 35,000 people and someone has mugged you off a bit.

"That's how it feels when I've been hit. You pride yourself on being able to either get out of the way or take it on.

"You don't want to be in that position again and let them get one up on you."

Hussain wrote in this Daily Mail column that "whoever you are and however good you are, you never like facing truly fast bowling".

"Once you have taken a serious blow like that, things can change," Hussain noted.