The shot stopper has not lined up for the team since his horrific showing in the Champions League final in 2018.
But Klopp had positive words for the 27-year-old before he headed to Union Berlin on loan.
He said to reporters: "It was always fair and honest. He always tells you what the situation is like.
"We always had a good relationship and never had a problem. His successes speak for themselves.
"He is currently one of the best coaches of the world.
"He said it (the move to Union) is a good step that I have the chance to distinguish myself here and that I can show everyone that I'm a really good one I am a goalkeeper."