De Telegraaf report that the 57-year-old was rushed to an Amsterdam hospital in an ambulance earlier this afternoon.
The Sun add that the Dutch football icon underwent underwent cardiac catheterisation.
De Telegraaf’s report, which came from Ronald’s wife – Bartina, adds that as Koeman received this treatment quickly, he is now in a stable condition and they suggest that he may be deemed fit to leave the hospital on Monday.
Koeman is regarded as a Barcelona legend, the former defender played a lot of his career in a sweeper role and he’s one of the players that transformed the way centre-backs are seen.
The set-piece specialist also won 78 caps for the Dutch national team in a playing career which also saw him represent Groningen, Ajax, PSV and Feyenoord.
Koeman has also enjoyed a successful managerial career after hanging up his boots, the Dutchman has been in charge of European clubs Vitesse, Ajax, Benfica, PSV, Valencia, AZ and Feyenoord.
The stalwart also managed Premier League sides Southampton and Everton, after those spells Koeman was named Netherlands boss in 2018.