Ex-Liverpool defender Babbel said: "Jens is not happy with mediocrity.
"That is understandable. Due to his age he will not have many more chances to win titles.
"Therefore the team have a duty. They have to show Jens that we are on the up.
"I have spoken to him and told him how pleased I would be if he stays. The whole team benefits from his personality. He knows in how high esteem he is held by us."