MONZA, Italy, Sept 1 (Reuters) - Michael Schumacher pulled out of a Ferrari test session on Wednesday and postponed his Formula One comeback.
"I don't think I will compete in the next two races,'' said the twice former world champion.
Schumacher had been aiming to return at the Italian Grand Prix on September 12, next round of the world championship, after breaking his leg in a crash at the British Grand Prix on July 11.
His absence from Monza is now likely to extend to the European Grand Prix at Germany's Nuerburgring circuit two weeks later.
Schumacher added: There were problems in my leg. They are too big to do a proper job. Basically, it is impossible to drive properly at the moment.
"We will stop the testing today, consolidate and I will have a meeting with my doctors on Sunday.''
Schumacher, who had limped into a news conference, said the conditions at Monza had made it particularly difficult for him. He completed only 27 laps and recorded a best time of 1 minute 26.90 seconds.
"The bumps on this circuit and the curves on this circuit are pretty severe. It is pretty difficult. I had pain all the way through and you can't drive like that. I took painkillers but it did not really help.''
World championship leader Mika Hakkinen covered 63 laps in his McLaren with a best of 1:25.90.
Hundreds of Ferrari fans had greeted Schumacher when he went out on the track in the morning. One banner declared: ``The king is back.''
In spite of his decision, the German said he was still recovering at the rate his doctors had predicted.
"After the surgery the doctor said I would not be back in the car for 12 to 16 weeks. Here I am after seven weeks. Maybe you can say it was too early, but we had to try. It is not a step back we just must take more time.''
Two world championship races remain after the European Grand Prix -- in Malaysia on October 17 and Japan on October 31.
Asked if he had deliberately delayed his return so as not to be forced into helping Ferrari's team mate Eddie Irvine in his world championship battle with Hakkinen, Schumacher said his prime concern was for the team.
"I and Eddie Irvine have always driven for Ferrari. I don't believe Eddie ever drove for me and my interest, and I wouldn't drive for him. We drive for the team.''
Schumacher said his advice for Irvine was ``drive fast and don't crash. It up to Eddie to deliver. There are four races to go and with only one point difference everything is possible, he has a good opportunity.''
The German also recalled his experience during the crash.
"It was not a nice experience. I was very soon aware of the problem but the worse moment was when I tried to get out of the car and I couldn't because my leg was stuck inside. I couldn't really see what kind of injury it was.''
Schumacher said he and Ferrari had asked the sport's governing International Automobile Federation to allow cockpits to be bigger for taller drivers. But he said he owed his life to the improved technology of the past decade.
"Ten years ago I would have gone up to Saint Peter and knocked on his door. And now here I am.''