JOIN USThe five-times major winner, 54, had surgery on the tumour in late 2008 followed by a course of chemotherapy and had been recuperating at his home in northern Spain.
“The family will provide information on his state of health when more news becomes available,” said a statement on the player's personal website (www.seveballesteros.com).
His family also expressed their thanks for the support they had received and added that any updates would be published on the website.
Ballesteros had four operations to remove the tumour following his collapse at Madrid airport in October 2008.
He appeared in public for the first time following the surgery in May 2009 when he went to watch local football team Racing Santander and was given a standing ovation.
Regarded by many as golf's greatest shot-maker, Ballesteros won 87 titles worldwide, 50 of them on the European Tour.
A winner of three British Opens and two Masters titles, he also helped revive Europe's fortunes in the biennial Ryder Cup team competition.