SUZUKA, Japan -- Michael Schumacher is retiring from Formula One racing again -- and this time, he says, "it might be forever."
Unable to duplicate the success of his prime, the seven-time F1 champion announced Thursday he will retire at the end of the season, bringing an end to the most decorated career the sport has seen.
Though Mercedes had announced last week that Schumacher would be replaced by Lewis Hamilton next season, there had been speculation the 43-year-old German could move to Sauber. He instead chose to end his career.
"Basically, I've decided to retire at the end of the year," Schumacher said at the Japanese Grand Prix. "Although I was able and capable of competing with the best drivers that are around, at some point it's time to say goodbye, and this time it might be forever."
Schumacher holds the record for championships and grand prix wins (91). He began his career in 1991 and won two titles with Benetton, then five for Ferrari. He initially retired in 2006, but came back to drive for Mercedes in 2010. The comeback has not lived up to expectations, with just one podium finish.
"It's without doubt that we did not achieve our goals to develop a world championship fighting car," Schumacher said. "But it is also very clear I can be happy with my overall achievements."
Mercedes team boss Ross Brawn was effusive in his praise of Schumacher. Brawn was also chief strategist at Ferrari when Schumacher and the Italian team became so dominant that the sport's authorities made several rule changes to even the level of competition.
"He's the most courageous racing driver of the century," Brawn said. "And I feel very privileged to have worked with Michael from the beginning."
Schumacher hasn't decided what he will do after the season, saying he just wants to focus on the final six races. He has struggled this season, and was issued a 10-place grid penalty for Sunday's race at Suzuka for causing a crash with Toro Rosso's Jean-Eric Vergne during the Singapore GP.
"There is no point in the need to make any decisions right now," Schumacher said. "I have options obviously but whatever it will be will be made in time."
Schumacher acknowledged he considered retiring even before the announcement of Hamilton's move to Mercedes.
"During the past month I was not sure if I still had the motivation and energy which is necessary to go on," Schumacher said. "It is not my style to do something which I am not 100 percent feeling for."
Schumacher holds the record for the most races won in a single season, with 13 in 2004. In 2002, he became the only driver in F1 history to finish in the top three in every race of a season, and set the record for most consecutive podium finishes.
Even though his comeback didn't work out the way he wanted, Schumacher said he learned a lot from the experience.
"Over the past six years I have learned a lot," Schumacher said. "For example, you can open yourself without losing focus, that losing can be both more difficult and instructive than winning, which is something I lost sight of in the early years."