With the way that Leverkusen top players are eager to leave the club I am really not happy because this will definitely going to have a negative effects on them as a club come next season because it will not be easy to bring new players and begin to gel into the team and start getting results because Leverkusen has champions League to play next season
It's always like that for a team like or a team in the level of Bayern Leverkusen, players who gained recognition during the campaign and attracted some admirers will likely leave to teams bigger than the current team they play for especially if they were instrumental to the team. They go in for bigger and better opportunities it's always been like that for majority of players. Again, sometimes change of manager somehow affects wether a player would stay or leave. Let's assume Alonso was still with the team, I'm not sure most of this players leaving now will want to leave.