Steven Smith will need to bat against top pace within the next three days and show no further signs of concussion in order to be passed fit for the third Test at Headingley on Thursday, admitting he did not want to return unless he was "100% fit" to play in the next chapter of this Ashes series.

While expressing hope that he will be able to play at Leeds, Smith conceded that the "quick turnaround" between the second and third Tests would provide an obstacle for his return from what he described as a "mild concussion" resulting from a blow to the neck from Jofra Archer on day four at Lord's - a diagnosis that lead to him becoming the first concussion substitution in international cricket.

"It's obviously a quick turnaround between Test matches," Smith said. "I'm going to be assessed over the next five or six days, each day a couple times a day to see how I'm feeling and progressing and I'm hopeful I will be available for that Test match, but it's certainly up to the medical staff and we'll have conversations. It's certainly an area of concern concussion and I want to be 100% fit.

"I've got to be able to train probably a couple of days out and face fast bowling to make sure my reaction time and all that kind of stuff is in place. There's a few tests I'll have to tick off and I guess time will tell.

"I'd love to be out there trying to keep performing and try help Australia win another Test match but I think the right decision's been made and I'll obviously be monitored very closely over the next few days with a pretty quick turnaround in between Test matches and I'm hopeful I can make a recovery and be okay for that."

Speaking about how he felt on the fifth morning, Smith said his condition had deteriorated relative to what it had been in the hour after he was hit by Archer, at the time passing the concussion tests he needed to in order to resume his innings.

"I started to feel a little bit of a headache coming on last night, probably as the adrenaline got out of my system," Smith said. "I was able to get a good sleep in, which is somewhat rare for me. But woke up feeling a little bit groggy and with a headache again, so had some tests done and upon some further assessments deemed to be a mild concussion unfortunately.

"We did a test this morning here at the ground, did one last night and results changed slightly and unfortunately that and how I'm feeling have contributed to me being ruled out for the rest of the Test match. Yesterday when I came off the ground the results were normal. I passed all the tests and felt fine, felt normal. I was allowed to go back out and bat, upon discussions with the team doctor and the coach as well. They were both happy and I was comfortable as well, so we were all happy and I was able to go out and continue batting.

"I didn't have any real pain in my neck yesterday when I touched it or when anyone else touched it. Today I do have a bit of pain there, whether that's some swelling or what I'm not sure. Perhaps that's leading to me having a headache and feeling a bit groggy. In regards to the arm, the arm feels pretty good today. It's quite a good bruise I have on it and it's feeling a lot better. The movement I have in it is far greater than I had yesterday and that feels really good."

In explaining why he did not use a stem guard to protect the back of his neck, Smith said that he would now have to consider adopting the extra protection in the wake of his injury. "I along with a few other players in the team find it a little bit different, uncomfortable to what we're used to," he said. "For me I feel a little bit claustrophobic when its on, I feel like I'm enclosed and not overly comfortable. But it's certainly something I need to probably have a look at and perhaps try in the nets and see if I can find a way to get comfortable with it.

"Australia's the leader in bringing the concussion subs and rules around concussion in the domestic competition back home. We're very thorough in the way we deal with knocks to the head and neck to ensure that the safety and health of a player is of paramount importance. The doc's had a pretty close eye on me since I came off the field yesterday and I've been assessed and asked a lot of questions over the last 20 hours or thereabouts, and unfortunately I've declined in the way I've felt over that time."