Cape Town - Sergio Aguero was taken to hospital for medical checks after he reportedly fainted during Argentina's 4-2 friendly loss to Nigeria in Russia on Tuesday.
The Manchester City striker was taken ill at half-time and was taken to a local hospital. He later rejoined the Argentina squad.
Aguero played in the first-half and scored in the 36th minute before being substituted at half-time in Krasnodar.
The Argentine Football Association said in a statement that the 29-year-old "had a blackout and was taken (to hospital) so routine examinations were made only as a precaution."
The Argentina team doctor Donato Villani later told the press: "He felt bad twice, and with the medical history he has, since he was operated on when he was 15, we wanted to be sure it was nothing.”
Aguero has previously suffered a heart ailment.
"We took him to hospital to make sure everything was normal, we prefer to wait to be sure."
Manchester City also released a statement about the incident.
"Sergio Aguero has been cleared by doctors to return to Manchester as planned after suffering a dizzy spell during Argentina's 4-2 defeat by Nigeria in Krasnodar today,” the club said in a a statement.
"Sergio never lost consciousness, and was taken to hospital for precautionary medical checks. He will be assessed by the club's medical team ahead of this weekend's Premier League trip to Leicester City."
The friendly match saw Argentina throw away a two-goal lead.
Ever Banega and Aguero had put Argentina in front only for Kelechi Iheanacho to pull a goal back for Nigeria just before half-time.
The Super Eagles then added three goals in the second-half through Arsenal’s Alex Iwobi (2) and Brian Idowu.