1. DK has proved himself many times
With World Cup coming close one would expect the main players to get as much as game time possible. But that is not the case with DK. He has always been a fail-safe option on which India can bank on.
Moreover he is the captain of KKR in IPL. This means that he needs to play at least 14 games in the IPL. As a result the management might have wanted to give him some rest.
But if the players selected in place of DK performs well, then the Tamil Nadu-born player might miss the plane to England. But with the experience that Karthik brings to the squad, India has the luxury to fiddle with the team combination.
So keeping all these reasons in mind, DK should not hang his head in disappointment. Who knows Karthik might finish the World Cup in style like his legendary predecessor who did it in 2011.