Ashes 2019: Steve Smith admits he felt ‘groggy’ this morning after being ruled out with concussion

Smith was hit on the neck by a bouncer bowled by Jofra Archer and could now miss the third Test as he begins the concussion protocol

Steve Smith admits he has "declined" after feeling "groggy" this morning before being diagnosed with a concussion to rule him out of the fifth day of the second Ashes Test at Lord's and potentially the entire third Test.

The Australia batsman was hit on the neck by a bouncer from England bowler Jofra Archer on day four, forcing him to initially retire hurt before returning to make 92.

But now Smith has been diagnosed with concussion after reportedly sleeping well but waking up with a headache and feeling dizzy.

"I started to feel a little bit of a headache coming on last night as the adrenaline I guess 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.

"I had some tests done and upon some further assessment, deemed to be a mild concussion, unfortunately, and I've been ruled out for the rest of this Test match."They've declined a little bit. We did a test this morning here at the ground and did one last night and the results changed slightly. Unfortunately that and how I'm feeling have contributed to me being ruled out for the rest of the Test."

Cricket Australia claim 30 per cent of concussions in Australia cricket are delayed and can take 24-48 hours to emerge. Despite that, Smith was sent back in to bat 40 minutes after the incident.

Smith will not be allowed to train or play for six days - meaning he is unlikely to be unavailable for the third Test at Headingly, which starts August 22.

Australia replaced Smith with Marnus Labuschagne as play continued on day five, the first concussion replacement in the history of the game.

Cricket Australia would not completely rule Smith out of the Leeds Test, but admitted the short turnaround is not in his favour.

A statement read: “This will be considered over the coming days but the short turnaround to the next Test is not in his favour.

Smith reacts after being hit by Archer (Getty)

"Steve’s fitness will be assessed on an ongoing basis.”

Rain delayed the start of play at Lord's, with England resuming 104 runs ahead in their second innings on 96/4. Australia lead the five-match series 1-0.