Steve Smith is out of day five of the second Ashes Test after waking up with dizziness.
It is unconfirmed yet whether he will take part in the third Test, with a quick turnaround surely making his participation unlikely.
Confirmation from Cricket Australia that @marnus3cricket is the named concussion substitute to replace @stevesmith49.
— Test Match Special (@bbctms) August 18, 2019
It's the first time we'll see a concussion replacement in Test cricket.
Live: https://t.co/8TTqeG2FiK#bbccricket #Ashes pic.twitter.com/nbFRdFicDP
Marnus Labuschagne has taken the field and will play in his place after Australia successfully applied for a concussion substitute.
Acording to Cricket Australia, Smith passed a series of concussion test, but woke this morning with a "bit of a headache and a feeling of grogginess"
CA have achieved a rare piece of unwanted history by becoming the first team to apply to the ICC for a concussion substitute under the new protocols, which came into action on August 1.
1 - Marnus Labuschagne is the only batsman to post 1,000+ @CountyChamp runs this season (1,114); averaging 65.5. Sub. #Ashes pic.twitter.com/ciY4cIsLfx
— OptaJim (@OptaJim) August 18, 2019
"Steve has been closely monitored by medical staff overnight and this morning reported that after sleeping well, he woke with 'a bit of a headache and a feeling of grogginess.'" a Cricket Australia statement said
"As part of the Cricket Australia concussion protocol, repeat concussion testing of Steve Smith was also performed this morning and 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"On that basis Steve has been withdrawn from the match by team doctor Richard Saw and the Australia team will lodge an application for a concussion substitute with the ICC match referee in line with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.
"Cricket Australia statistics show that 30 percent of concussions in Australian cricket are delayed. It is not uncommon for players to pass their tests and feel well on the day of an injury and then display symptoms 24 - 48 hours later.
"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.
"Despite the unfortunate nature of what has happened, the positive is that the concussion protocol, including the availability of the concussion substitute, which has been recently brought in has served its purpose. A player is no longer under pressure to take the field when he or she displays symptoms of concussion and a side is not disadvantaged having lost a player to a blow to the head or neck.
"Cricket Australia is proud to have been leaders in this area, having introduced concussion substitutes in domestic cricket and worked with the ICC to introduce them in international cricket."
More to come.