I saw the interview (now banned in youtube),
The interview should be this one (
http://derpoehler.com/2013/05/01/mats-hummels-on-mario-gotze-switch/)
He said: “Mario Götze is one of the best 10 players on the planet now and therefore it was shocking for us to hear that he will leave. I didn’t really sleep that night, because I had heard it only one day before, – as some other of our team members too. We have talked a lot about this topic internally in the meantime”
“I like it very much when you are in a team and you can say this is “my team”, I like it to improve performance together with this team and the team mates continuously and I won’t join a ready well-performing team and easily get three titles. Personally, for my carrer, it really doesn’t matter not merely that I have won eight Championship titles and seven Cup titles, but rather that I have won exceptional titles. The three titles that we have won in the last two years with Borussia are such exceptional titles.”
“The thing with Mario is a sign that we haven’t been held in high esteem as the Top 4, Top 5 clubs in the world, but you have either the chance to contribute you part to get your club to this level or you can switch to such a club.”
“That is what it makes very difficult to all of us, because we lose a player who exactly knows how we think, who is part of this club from his youth on and still prefers another German club. When Shinji signed at Manchester or even when Lewy should go, this is more normal because they are not from Germany, but so it is hard.”