Ralf says big brother Michael is close to retirement

Michael Schumacher may retire from Formula One at the end of the season, his brother Ralf claimed today.

World champion Schumacher has dominated motor racing for a decade but has endured a tough start to the season with Ferrari as the Renault and McLaren drivers continue to set the pace in this year's championship.

"I don't believe Michael will be driving for very much longer," Ralf Schumacher said ahead of Sunday's US Grand Prix at Indianapolis.

"He'll stay as long as he's having fun with it. The success in past years was obviously a lot of fun for him but he's not having that fun at the moment and I'm very anxious to see what will happen if it stays like that until the end of the season."

The seven-time world champion looks unlikely to extend his record to eight this season. The German is lying fifth in the drivers' championship, way behind points leader Renault's Fernando Alonso.

Schumacher's contract expires at the end of 2006 and he will let Ferrari team boss Jean Todt know his intentions by the end of this year. BMW-Williams driver Ralf believes Ferrari are on a downward spiral.