Quote from the article:

Kimi Raikkonen makes a comeback to F1 in 2011
Wednesday, December 15, 2010

Norbert Haug and the Mercedes management have confirmed that 2003 and 2005 runner-up and 2007 F1 World Champion Kimi Raikkonen will end his 1 year F1 sabbatical and come back to replace Michael Schumacher at the Mercedes GP team for 2011. Sources say that Michael wasn't fully motivated and has agreed to cut the contract short in light of his neck problems and decreasing race performance. Also, his wife...
Full Article here: http://www.gpupdate.net/en/f1-news/249371/kimi-raikkonen-comes-back-to-f1

And from Formula1.com as well: http://www.formula1.com/news/headlines/2010/12/11603.html

Well, this is surely going to make all Kimi fans jump up and dance with joy!