Salah will leave Anfield on a free transfer at the end of the season after announcing the mutual termination of his contract, while Andy Robertson is also departing. The Egyptian's exit leaves a considerable hole in a squad that will also be without the left-back who provided cover and competition for the past nine seasons.
Speaking to Sky Sports, Slot was unambiguous about the financial reality of this summer's window compared to the last.
"I would not use the expression 'big summer ahead of us' because we do not know exactly what will happen. At the moment we know that Robbo and Mo will leave. But we also know that Konstantinos Tsimikas could return."
The Greek left-back is currently on loan at AS Roma and is expected to come back to the club in the summer, alleviating some of the pressure on the full-back position.
On the task of replacing Salah — who scored 257 goals and provided 122 assists across nine seasons at the club — Slot made clear that no single player will fill the void.
"We must find a way to replace a player like Mo, which will never be easy if you look at the numbers he has produced for eight or nine years. It is impossible to replace him with one player, so we will have to spread his goals among the other elements of the squad."
He was frank about the financial implications of operating at the top level of the market.
"As we showed last season, when players leave you usually try to replace them. At our level, however, this involves very high costs and a lot of money."
Among the attacking targets being linked with the club, RB Leipzig winger Yan Diomande has emerged as one of the most prominent. The 19-year-old Ivorian has scored 13 goals and contributed nine assists across all competitions this season and is rated at around £87 million by Leipzig — a figure that illustrates precisely the challenge Slot is describing. Liverpool are also reported to be monitoring Ajax's Mika Godts.
The summer window will open on 29 June. Salah's final likely Anfield appearance will come against Brentford on the final day.