Despite last season's Premier League title success, Slot is under pressure after nine defeats in the las 12 games.
And ahead of Sunday's trip to West Ham, Kieft wrote in De Telegraaf: "By signing (Florian) Wirtz and (Hugo) Ekitiké for €137m and €80m respectively, Liverpool took a costly risk. The midfielder and striker possess quality. Nevertheless, this offers no guarantee that they can compete in English football. Success in the Premier League often requires more.
"After difficult and lengthy negotiations, everyone in Liverpool was delighted with the signings of captain Virgil van Dijk and Mohamed Salah, the two mainstays of last season’s success. However, they are unrecognisable.
"The defence with Van Dijk concedes an awful lot of goals. Salah’s performance is minimal. But surely those two haven’t suddenly forgotten their skills?
"All in all, Liverpool’s performances against Nottingham Forest and PSV were staggering. There are no clues to halt the decline. Even the magical Arne Slot can’t turn this around overnight. He can’t conjure up goals. And what no one thought possible could easily happen: Slot being fired after two or three more poor results."