It's happening. Sami Khedira will play for Arsenal next season unless the German midfielder himself decides to sign a contract extension with Real Madrid. But this will not happen, as Khedira wants to get more money than what he has been offered by the Spanish club. He will get that big contract in Arsenal and he will reunite with former teammate Mesut Özil and other German players like Per Mertesacker and Lukas Podolski.
With Khedira's departure and Toni Kroos' imminent arrival, Ancelotti has decided to change the team's style quite heavily to a more possession-oriented game. Expect Real Madrid to play with Luka Modric and Toni Kroos at the same time in what should also be a slower tempo.
Khedira and Kroos' moves should be official almost at the same time, and the announcements could happen this very same Wednesday. It should be noted that these two players are going through similar contract situations with their respective clubs.