Steve Smith has failed to recover from his concussion effectively ruling him out of the third Ashes Test due to commence on Thursday at Headingley.
Cricket Australia made the announcement on Tuesday declaring the world number two ranked batsman will have to sit out the Leeds encounter after being felled by a Jofra Archer bouncer in the previous game.
Smith was struck on the back of the neck - the area unprotected by the helmet - by a threatening delivery from Archer while he was batting on 80 in the first innings.
The force of the blow immediately caused Smith to drop to the floor face down as the England players and umpires gathered around him to inspect his well-being.
"Steve Smith has been ruled out of the third Ashes Test at Headingley, with coach Justin Langer confirming the news after the batsman sat out Australia's training session on Tuesday," Cricket Australia stated.
Smith's gradual improvement over the last couple of days had given hope of a return to the cricket action at Headingley but the team doctor Richard Saw felt he was not fit enough to resume batting duties.
He was seen in conversation with coach Langer on the morning of the training session as his teammates engaged in fielding drills.
The official confirmation of Smith's withdrawal from the squad was glumly received by the star batter as he stood disconcerted.
Smith staged a phenomenal return to conventional five-day cricket when Australia rode on the back of his twin centuries in the Edgbaston Test to win the Ashes opener by a massive margin of 251 runs.
His first Test game since the expiry of his 12-month ban owing to ball-tampering, Smith's batting heroics were constantly subject to raucous boos from a sea of hostile English supporters.
Despite the nasty blow to the side of the head, Smith came out to bat and added 12 runs to his total of 80 in the first innings of the second Test before shouldering arms to an in-swinging Chris Woakes delivery.
He was then ruled out of the final day on Sunday after complaining of "grogginess" with Australia managing to cling on to a draw to maintain the series lead.
The visitors were helped by a spellbinding knock from concussion substitute - the first of its kind in cricket - Marnus Labuschagne who warded off a bumper barrage from Archer to top-score with 59 in Australia's total of 154-6.
When Smith was struck on the head, he was guilty of not wearing the additional protection surrounding the area of the neck, which was introduced in the aftermath of Phillip Hughes' death in 2014.
Australia are still in search of their first Ashes triumph on English soil in 18 years and would be looking to extend their lead in their next meeting with the traditional rivals.
Meanwhile, Smith will have two weeks of rest to prepare for the fourth Test in Manchester scheduled to begin on September 4.