Smith, who was hit on the side of the neck by a vicious delivery from England paceman Jofra Archer on Saturday, woke with a "bit of a headache and a feeling of grogginess," Cricket Australia said. Smith retired hurt before returning to the middle 40 minutes later after passing concussion tests. Cricket Australia said Smith suffered a delayed concussion.
"As part of the Cricket Australia concussion protocol, repeat concussion testing of Steve Smith was performed this morning and demonstrated some deterioration from his testing, which is consistent with the emergence of the symptoms he was reporting," Cricket Australia said.
"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 to 48 hours later."
Marnus Labuschagne was approved as Smith's replacement after Australia applied for a concussion substitute, which was introduced to international cricket on Aug. 1. Smith could miss the third Ashes test starting in Leeds on Thursday. It would be a huge loss to Australia, with Smith hitting 144 and 142 in the first test at Edgbaston — won by 251 runs by the Australians — and then making 92 in the first test at Lord's.
"This will be considered over the coming days but the short turnaround to the next test is not in his favor," CA said. "Steve's fitness will be assessed on an ongoing basis."
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