Speaking to various media outlets in Seefeld, Austria, amid Hoffenheim's pre-season training camp, Baumann disclosed details of his direct conversation with Nagelsmann, who has since been replaced by Jurgen Klopp.
Discussing the bitter decision, Baumann revealed: "He [Nagelsmann] was sorry about how everything turned out in the end. I spoke with Julian ten days ago. We had already agreed to talk on the phone. Then we talked for almost an hour. I told him everything that was important to me.
"Of course, it was hard to swallow. I had this big goal. But I managed to give the team a lot of energy [from the substitutes' bench]. I think I laid the foundation from my side so that nothing stands in the way of success."