Both star centre-backs are fit this summer and participating in preseason with their teammates after missing much of last season.
However, Klopp says neither player is expected to start in their preseason friendly against Mainz.
He spoke after the team's 1-1 draws in two 30-minute matches against FC Wacker Innsbruck and VfB Stuttgart.
Klopp told the club website: "It would be a surprise, to me as well. They have looked really good in training and yesterday was the first day where they did very complex things, usually it is either offensive or defensive and stuff like this.
"We have to get there, step by step, but I don't expect them for Friday."