Asked about the existence of a release clause, Carro said, as quoted by Ben Jacobs: "No, but you don't need a clause. We have a very, very good relationship with Xabi and he knows we are a serious club. And at the end of the day, we're not going to force someone to stay if he doesn't want to stay. We want him to feel so happy and so good with us that he really only wants to stay and this is our objective..
"There is nothing on paper [allowing Xabi to leave for a former club]. But sometimes agreements that are not on paper are agreements as well. We know if he needs to do a move in the future we will be able to talk with each other. And I hope we will not need to do this because he will stay and be happy at Leverkusen."