Star Australia batsman Steve Smith was on Sunday ruled out of the remainder of the second Ashes Test in Lord's after being diagnosed with concussion caused by a blow to his neck from England seamer Jofra Archer on Day 4 on Saturday.
Smith was replaced by Marnus Labuschagne, who became Test cricket's first-ever concussion substitute who can bat in Australia's second innings.
Smith woke up on Sunday morning with 'a bit of a headache and grogginess', said a statement issued by Cricket Australia (CA).
Smith was forced to retire on Saturday while batting on 80 after being hit by the Archer bouncer. However, he cleared a concussion test and returned to the crease before being dismissed for 92.
Another concussion test was conducted before the fifth day's play as per CA protocol, which "demonstrated some deterioration from his testing which is consistent with the emergence of the symptoms he was reporting."
"On that basis, Steve has been withdrawn from the match by team doctor Richard Saw and the Australia team will lodge an application for a concussion substitute with the ICC match referee in line with the ICC protocol."
"In terms of Steve's availability for the third Test, this will be considered over the coming days but the short turnaround to the next Test is not in his favour. Steve's fitness will be assessed on an ongoing basis. Steve will undergo a precautionary scan on his neck on Sunday," the CA statement said.
The third Test begins in Leeds on August 22.
Smith was batting on 80 on Day 4 when in the 77th over a delivery by Archer hit him on the unprotected part of his neck. The medics ran into the middle from both sides, as the England players rushed to the former Aussie skipper immediately.
As Smith lay on his back before slowly getting back on his feet, he looked dazed. The medics forced him to leave the field with Australia at 203/6, still some way behind England's first innings score of 258.
Smith walked back to the pavilion to loud applause after helping his side out of a hole as he did in the first Test.
Smith, who at the outset did not want to leave the field, soon walked back but this time he was not as composed as he was before the knock to his neck, leaving a straight delivery from Chris Woakes which caught him plumb in front of the stumps for 92.