Initially, Smith passed a concussion test and was allowed to return to the field and complete his innings, but his condition worsened the following day.
Langer, who replaced Darren Lehmann as coach when the latter resigned following the ball-tampering scandal that blew up on the tour of South Africa in 2018, said losing Smith was as big a blow as England losing leading wicket taker Jimmy Anderson in the first Test.
Steve Smith has been ruled out of the third Ashes Test at Headingley due to the concussion.
Smith has two weeks to recover and prepare for the fourth test in Manchester, which begins on September 4.
Smith is in far better spirits compared to Sunday, when he became the first concussed cricketer to be substituted out of an global match.
But CA policy dictates the only opinion that matters is that of team doctor Richard Saw, which Smith and Paine have both publicly conceded. "When we followed the protocols, he was probably a couple of days off being fit to be selected".
Adams, a committed fan of the game and secretary of the Lord's and Commons Cricket Club, echoed the comments of Australian prime minister Scott Morrison, who called Saturday's booing of Smith a "total Ashes foul".
Steve Smith at Australian team training at Headingley.
Especially from Bayliss, the former NSW and Sydney Sixers coach who mentored Smith at the early stage of his career. Manus Labuschagne came in as Smith's replacement and even scored a fighting half-century to help Australia draw the second Test and preserve a 1-0 lead in the five-match Test series.
Langer and counterpart Trevor Bayliss agreed Smith will leave an vast void for Australia to cover. It's something you never like to see and certainly brought flashbacks from that game a few years ago when Hughesy (Philip Hughes) got hit.
"Just glad to see him get to his feet. Hopefully he's right and able to play in the next match".