By Alan Baldwin

LONDON (Reuters) - The possibility of Michael Schumacher announcing his retirement hangs over Sunday's Italian Grand Prix.

Even if Ferrari's seven times world champion wins at Monza and slashes Fernando Alonso's overall lead to single figures with three races remaining, all could be overshadowed by what happens afterwards.

With Germany's mass-circulation Bild flagging up Schumacher's impending retirement on Wednesday, there is every reason to fear that the greatest and most remarkable career in Formula One history is coming to an end.

If that proves to be the case, Monza will be Schumacher's European farewell to the Ferrari faithful at the temple of Italian motor racing.

Ferrari, who are expected to sign Kimi Raikkonen from McLaren, have promised an announcement after the race. Until then, they and the German are keeping the secret to themselves.

"Of course I know that Ferrari's announcement is being eagerly awaited," said Schumacher on his Web site.

"We announced last week that it will be made on Sunday following the race because we want to do our best in focussing on the race, and of course I'm sticking to this agreement.

"So all I can do is ask everyone to understand that I don't want to touch on that subject until next Sunday."

MONZA MEMORIES

If the 37-year-old does announce he is leaving at the end of the season, Monza would be a fitting place to salute his legions of fans and bask in their warmth.

It was at the Milanese circuit, with Benetton in 1991, that the German scored his first points in only his second grand prix.

"The first time I raced, I never had any idea that I would make it so far," he said in a 2003 biography penned by his spokeswoman Sabine Kehm.

"That was in Monza in 1991 when I drove further than 500 metres for the first time (in a grand prix). I got into a wheel-to-wheel with the great Ayrton Senna because he was having difficulties right at the beginning of the race and I was able to chase and attack him.

"That was the moment I realised that we all only cook with water. If someone is sitting in the right car at the right time, they can beat anyone. I realised that then, and I still believe it today."

It was at Monza, in 2000, that he cried openly after equalling the late Senna's 41 wins in a race that also saw a marshal fatally injured.

After finishing third in the previous Turkish Grand Prix won by team mate Felipe Massa, Schumacher can hope to return to the top of the podium for the 90th time.

A Ferrari one-two led by Schumacher would cut world champion Alonso's lead from 12 points to at least eight while the Italian team overturned their two-point deficit to Renault in the constructors' standings.

"Our strategy has to be attacking," said Schumacher on his Web site. "We have to close the gap and the only way to do that is by consistently putting on the pressure and pushing hard.

"It's not the first time we've been in a situation like this and our experience will be of help to us. I think our chances of turning the championship around are very good," he added.

"Lots of things can still happen in the remaining four races. I think we still have every reason to dream of winning both titles."