The Croatian is on the verge of a €12m (£11m) move to Russian champions Zenit St Petersburg that should go through once the Premier League season concludes.
But Klopp said: “As long as nothing is decided, we don't speak about these things.
“If you don't speak about the potential departure of a player, then we can't speak about a potential replacement!
“If there is something to say, then we will. But not at the moment, nothing."