The Brazilian goalkeeper faces several weeks out, with Kelleher now stepping up.
Ahead of their Europa League tie with LASK Linz, Klopp said: "Exactly that, that's why we knew we wanted to have Caoimhin here – for these moments. Nobody, Caoimhin [included], wanted Ali to get injured but if these kind of things happen then you need the strongest possible option and that's Caoimhin for us.
"That's the only positive about that, to be honest, we can put in Caoimhin and that's fine. Now he gets the opportunity, which he deserves anyway, he would have played tomorrow night anyway, that's clear.
"But now he will have a few more games and hopefully he can show his full potential."