Gilberto Silva
Arsene has a pattern in players going off for national duties at crucial time?
Gilberto went to play for Brazil as a captain (and who can blame him to do so) during last summer. Comes back late to the team, missed pre-season and important CL qualifiers. Gilberto lost his captaincy in Arsenal and also his midfield place.
Toure went for African Nations Cup, during a very important time as the title race build up. Toure came back tired and also nursing an injury. Never quite got back his CB position but instead being played off position in RB and even Song and Senderos is playing in his preferred position.