Ashes 2019: Concussion rules out Steve Smith from third test

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

Smith, suffering a delayed concussion after being struck on the neck by a Jofra Archer bouncer at Lord's, will not take the field when the series continues in Leeds at Headingley.

Smith is in far better spirits than on Sunday (local time), when he became the first concussed cricketer to be substituted out of an international match, but the tight turnaround was always going to count against him.

The former skipper failed to train on Tuesday (local time), when the touring party had their first session since arriving in Leeds.

Smith had a long chat with coach Justin Langer while inspecting the pitch and talked with team doctor Richard Saw, cutting a dejected figure in both conversations.

Shadow batting and walking was as rigorous as it was to get for Smith, who debriefed with mentor Mark Taylor after finally giving up hope of facing England.

The absence of the talismanic run glutton shapes as a major blow to Australia's hopes of retaining the urn with victory in Leeds.

Marnus Labuschagne, having delivered a match-saving 59 while filling in for Smith on day five at Lord's, will need to step up again.

The pressure will also rise on Travis Head, who has been Australia's best-performing batsman on the tour outside Smith.

"It (the Lord's draw) showed that without Steve, we were able to get the job done which is a positive," Head said.

"Steve is obviously in great nick and playing beautifully at the minute.

"But obviously, Marnus came in and played beautifully. He has been fantastic over here in the county season - got a lot of hundreds.

"Wadey got a hundred at Edgbaston, so I think we have got guys who are in form .. we have got the batting in the sheds that can do the job."

England coach Trevor Bayliss admitted the absence of "the best batter in the world" would obviously improve his team's chances of squaring the five-test series.

"But as his replacement showed in the last match, he's more than capable," Bayliss added.

"The winner of this Ashes is not going to necessarily come down to one player from either side.

Labuschagne, hit on the helmet by Archer in the second test, suffered another scare on Tuesday (local time) when struck on the grille by Mitchell Starc in the nets but was given the green light to continue batting.

Cricket Australia's concussion and head trauma policy dictated the only opinion that mattered in Smith's selection battle was that of Dr Saw, who as kept busy throughout the second test as batsmen suffered a stack of blows to the body, arm and head.

The medico will continue to assess Smith regularly and remains in sole control of his gradual return to activity.

"He's looking after him pretty well - he is in good hands," Head said.

Smith's setback increases under-pressure Cameron Bancroft's hopes of retaining his spot at the top of the order, although selectors will likely still consider calling up Mitch Marsh or Marcus Harris.

AAP