Batsman Nkrumah Bonner has been ruled out of the remainder of the first Test against South Africa after sustaining a concussion.
According to Cricket West Indies, he has been replaced by left-handed batsman Kieran Powell.
Bonner was struck on the helmet while batting in the West Indies first innings on Thursday, and passed the on-field concussion assessment.
He underwent further medical assessments after coming off the field, and was subsequently diagnosed as having a concussion.
ICC Match Referee Sir Richie Richardson approved the West Indies request for Powell to come into the match as a concussion substitute.
As per the ICC match regulations, Powell will be permitted to bat in the West Indies second innings.
The Windies had a disastrous start to the match, having been bowled out for 97 on Day One today.
At stumps, South Africa were 128/4, a lead of 31 runs.