Michael Schumacher may retire at the end of the season because he is not having fun at the moment, according to his brother Ralf.
Ferrari driver Schumacher has long dominated Formula One but has endured a tough start to the season as the Renault and McLaren drivers continue to set the pace with Fernando Alonso out in front.
"I don't believe that Michael will be driving for very much longer," Ralf Schumacher told German newspaper Sport Bild.
"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; 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, currently lying fifth in the drivers' championship, as the 36-year-old has struggled in the new model Ferrari, largely due to Bridgestone tyre problems.
Schumacher's contract expires at the end of next year and he will let team boss Jean Todt know his intentions by the end of the current calendar.
