The 32-year-old German coach added: "We as a club always find solutions and I'm sure in the future we will find solutions. That's our model, we have to accept it. I think that as a club we have proved we are not only selling big players. We have had offers for other players - big offers for [Kaoru] Mitoma and other players. We proved that we are not selling every player.
"Of course, there were some big players who left the club, but there are new players that are coming into the club. With the togetherness we have, with the team chemistry we have, we can compete with the big teams, and we can compete with teams who might be individually better than us."