Wales prop Tomas Francis was forced to leave the field after just minutes on the pitch after taking a knee to the head in a tackle.
The 30-year-old front-rower came on for Wayne Pivac's men in the second half of their opening Test against the Springboks in place of Dillon Lewis, but was soon departing after putting in a low tackle which resulted in the prop apparently being knocked out.
The game in Pretoria was halted for around seven minutes while he received medical attention, before he was removed from the field on a stretcher via a buggy with his head in a brace. Fans inside the sold-out Loftus Versfeld Stadium applauded as he exited.
Pivac confirmed during his post-match press conference that the Osprey is ruled out for the second Test and could yet miss the series finale, which you can read more about here.
SIGN-UP: Get the latest rugby news delivered straight into your inbox for FREE!
The worrying scenes played out just over four months after he was at the centre of a concussion controversy following an incident against England during the Six Nations.
Former Wales centre Jamie Roberts, commentating for Sky Sports, said: "The time you've got to make that decision is such a small period of time. When you do go low, you run the risk of knees and elbows potentially causing injuries. He did get his head on the wrong side."
Wales were enjoying a 18-10 lead at the time, with Dillon Lewis returning to the fray to complete the game after initially being substituted. Pivac's men later suffered a cruel 32-29 defeat to the 'Boks, who won with the last kick of the game.
During the February Six Nations encounter at Twickenham, TV footage showed Francis staggering near his own try line following a clash with team-mate Owen Watkin and he appeared to use pads of the posts to hold himself up. After being removed for a HIA, which he passed, he was permitted to return to play. But a review panel later concluded he should have been immediately removed from the field.
Read next:
- Dan Biggar denies any wrongdoing in moment that lost the game
- Wales suffer agony in Test match for the ages as excruciating turning point sees history slip away
- South Africa v Wales match halted for seven minutes amid concerning scenes
- Australia v England halted as Tom Banks suffers gruesome injury and Sky Sports commentators apologise for replays
- Australia giant sent off for headbutting England star who pulled his hair
- All Blacks star's 'sickening' challenge against Ireland sparks furore as officials stand accused
