Both bosses are facing selection decisions for the fourth-round tie at Anfield.
For the last five matches, Slot has only been able to name a maximum of four senior players on the bench as he deals with a quartet of long-term injuries.
Although he has midfielder Dominik Szoboszlai back from suspension he has lost Wataru Endo most likely for the rest of the season after a serious ankle injury in Wednesday’s Premier League win at Sunderland.
It is believed on Merseyside that there is little chance of him using younger players to give his first-choice players a break.
Although he has eight days before their next fixture Slot said three matches in a week is testing his selection decisions.
The Liverpool boss said: “It’s another challenge. It took me a long time to get to sleep because I was constantly considering what options I have for the line-up and what I should do
“Do you play the same players again or is it a moment for the others, but which others in which position? I need another 24 hours to decide on my line-up.”
Slot can bring in Szoboszlai, first-choice left-back Milos Kerkez, Joe Gomez, midfielder Curtis Jones and fringe forwards Federico Chiesa and Rio Ngumoha, as well as back-up goalkeeper Giorgi Mamardashvili.
However, it is the key positions of centre-back where he has few options, highlighted by the fact in the last round against League One Barnsley he started captain Virgil van Dijk.
The Netherlands captain, who has played every minute in the Premier League and Champions League, has scored twice in his last five matches after just two in his previous 31 this season as Liverpool have finally started to see an improvement in their set-pieces.
“Vital of course because if he is not playing there are no options left (at centre-back),” Slot said of Van Dijk’s importance.
“He has been fit every time and I’ve said before how big of an accomplishment that is for a player of his age because he’s not the youngest any more and plays every three days.
“It tells you what he does off the pitch for recovery but also his mental strength that he is not only able to stay with the team but also brings in very good performances and lead the team on and off the pitch by example and that is also what he did on Wednesday night.”