MADRID, Spain -- Seve Ballesteros was in stable condition Wednesday after the 51-year-old golf great had surgery on a brain tumor a day earlier.

Officials at La Paz Hospital said were no complications from the surgery. Spanish state news agency Efe reported the operation lasted 12 hours.

The hospital said a sizable part of the Spaniard's tumor was removed. It was not immediately known if it was malignant and it would be several days before the results were announced.

"At the moment he is conscious and stable, although he will not be able to receive any visitors in the coming days until he has recovered from the surgical process," the hospital said in a statement.

The hospital said Ballesteros was in the intensive care unit. It said there would be no further statements about him until he is moved from the unit, most likely next week.

Ballesteros had been expected to undergo only a biopsy on Tuesday, but Spanish newspaper Marca reported Wednesday that doctors decided to operate because of the seriousness of the situation.

The surgery was thought to be a resection of the tumor, a procedure to remove as much of the tumor as possible before radiotherapy or chemotherapy is commenced.

The newspaper, which added that Ballesteros' ex-wife Carmen and their three children were at the hospital, stated that the surgery lasted 12 hours, although in a later report it was put at seven hours.

The Spanish superstar quit the sport last year after back problems contributed to a sharp decline in his game. He was also found to have an irregular heartbeat when admitted to hospital shortly before his retirement announcement.

Ballesteros had issued his own statement on Sunday evening thanking all his fans for their messages of support.

That has included many of the players who are the stars of golf today and were inspired to take up the sport by his thrilling five major victories, his climb to the world No. 1 spot and his role in making the Ryder Cup the spectacle it now is.

England's Steve Webster paid a glowing tribute to Ballesteros as he prepared for his defense of the Portugal Masters at Vilamoura.

"Seve's my hero,'' said Webster. "Growing up, he was my favorite and from the first time we played together he always came to me and asked how I was doing or if I wanted a practice round.

"He just inspired me. I would love to win this week and give him a pat on the back because when I won in Italy (in 2005) I got a letter from him out of the blue and I've got it hanging up at home," he added. "He signed it saying 'Congratulations and a lot more will come out of your career'. I saved a voicemail on my phone when he phoned me up after winning this as well.

"He's always been very special to me and my fingers are crossed that everything goes well," he explained. "He made things happen where nobody else can, I don't think. Tiger is an amazing golfer, but Seve just had that maybe something just a little bit special about him.''

Ballesteros, winner of three British Opens and two Masters, briefly lost consciousness and was admitted Oct. 6 to the hospital, where the tumor was discovered. On Monday, he acknowledged having a tumor and said he faced the "hardest challenge of my life."

Ballesteros, who won a record 50 tournaments on the European Tour, retired last year because of a long history of back pain and has since concentrated on golf course design.

Ballesteros transformed European golf. When the Ryder Cup was expanded to include continental Europe in 1979, Ballesteros helped beat the United States in 1985 to begin two decades of dominance. He also captained Europe to victory in 1997 at Valderrama, Spain.

Ballesteros and Jose Maria Olazabal of Spain are the most formidable partnership in Ryder Cup history, with 11 wins, two losses and two halves.

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