Seve Ballesteros is reported to be in a stable condition in a Madrid hospital after fainting.
Spanish news agency EFE stated the five-time major champion, who retired from competitive golf last summer soon after his 50th birthday, was undergoing tests.
In July last year nephew and manager Ivan Ballesteros said the star was found to have an irregular heartbeat, but that it was nothing too serious.
At the same time Ballesteros issued a statement to reassure his "friends and admirers" around the world that he was doing "perfectly well".