Mazraoui had to be substituted during the first half of United's goalless draw against Aston Villa in the Premier League. Victor Lindelof replaced him at right-back.
The 26-year-old, who was making his tenth appearance for the Red Devils following a summer move from Bayern Munich, subsequently pulled out of Morocco’s squad for his nation’s Africa Cup of Nations qualifiers against the Central African Republic.
According to Manchester Evening News’ Samuel Luckhurst, Mazraoui complained of heart palpitations and went under the knife for a ‘minor precautionary corrective procedure’ to correct the problem.
Mazraoui is likely to be unavailable for at least a month, with United set to be without the Moroccan for their clash with Brentford after the international break on October 19.
In January 2023, Mazraoui was diagnosed with an inflammation of heart tissue after suffering from Covid-19 at the 2022 World Cup in Qatar, which meant he was sidelined for around six weeks.
‘Noussair Mazraoui is out initially after a Covid infection,’ a statement from Bayern Munich read at the time.
‘A follow-up examination in Munich after the World Cup revealed a mild inflammation of the pericardium, which the defender will now cure.’
Harry Maguire was also forced off in last Sunday’s stalemate at Villa Park and the centre-back, formerly United’s captain, has since confirmed that he would be unavailable for a number of weeks.
‘Frustrated to pick up an injury at the weekend,’ the England international told his followers on Instagram on Tuesday.
‘Will be a few weeks on the sideline for me but I’ll come back stronger.’
More to follow.