Simplify the following text for a Grade 8 native English-speaking person.
Original: Nico Rosberg was announced as the team 's first driver on 23 November 2009 and on 23 December 2009 , seven-times world champion Michael Schumacher announced that he will be returning to Formula 1 , this time with the Mercedes team .
Simplified: Nico Rosberg was announced as the team 's first driver on November 23 , 2009 . On December 23 , 2009 , seven-time world champion Michael Schumacher announced that he will be returning to Formula One with the Mercedes team .