Chris Rogers has been diagnosed with a vestibular injury, which has affected his inner ear and his balance.
Australia remain hopeful opener Chris Rogers will feature in the third Ashes Test, despite requiring further specialist treatment for an inner ear problem.
Rogers was overcome by dizziness as he retired ill on 49 on Sunday, after being struck on the helmet by a delivery from England paceman James Anderson on Friday, and it had been feared he suffered a delayed concussion.
The 37-year-old, however, was cleared of concussion on Wednesday, instead diagnosed with a vestibular injury that has affected his inner ear and consequently his balance.
Rogers, who scored 173 in the first innings at Lord's, stayed behind in London to undergo more tests but he could still take part at Edgbaston.
"If he continues to improve the way he does, he should be back playing cricket fairly soon," Australia doctor Peter Brukner said.
"But as to exactly when, we can't say. We certainly haven't ruled him out of next week's Test, it's just a matter of seeing how he goes over the next 48 hours.
"But at this stage we're optimistic he'll be able to play next week."
Rogers, who told fellow opener David Warner that he saw the Lord's grandstand moving, crouched to the ground after just two overs of play on Sunday.
The veteran was assisted from the field and played no further part as Australia levelled the Ashes at 1-1 following their resounding 405-run win.
Rogers will have further tests on Thursday and Friday.
"There are different components of the vestibular and balance system and there's various tests that can identify which of these components is working and which one is damaged," Brukner added.
"He'll also have some treatment, there's a physiotherapist who specialises in this area who is going to see him on Friday.
"There are various techniques they can use to help resolve some of these issues. He seems to be improving very steadily and it's a little bit early to say what's going to happen.
"But he's basically resting in his room, reading his Kindle. He's just taking it easy for a couple of days You manage this really similarly to the way you manage a concussion, you basically wait until the symptoms have resolved and once the symptoms have resolved, you start increasing the activity."
Rogers missed both of Australia's Tests in the Caribbean before the Ashes tour began due to concussion, after being hit in the helmet at training.