MatchEverton v Liverpool: Merseyside derby team news
Arthur completed a loan switch from Juventus on transfer deadline day, though Klopp reported on Friday afternoon the new No.29 may not receive international clearance in time for the 12.30pm BST kick-off.
"My information is it will not happen until tomorrow, the international clearance," Klopp said at a press conference. "We all hope he will be fine for Napoli."
Liverpool are set to be boosted by the return of Diogo Jota (hamstring) and Darwin Nunez, the latter eligible for selection again after serving his three-match Premier League suspension.
But Jordan Henderson is ruled out with the issue that forced him off in midweek against Newcastle United, joining Naby Keita, Thiago Alcantara and Alex Oxlade-Chamberlain as midfield options unavailable to Klopp.
The Reds manager revealed: "He [Henderson] is definitely out, he is injured, but the extent I don't know."
He added: "Diogo probably will be in as well, he trained yesterday with the team first time. He will train today.
"I have to make a decision, does it make sense that we involve him already or not? But if, it is the first time we have five attackers – sounds like Christmas!"
On the possibility of Nunez making an immediate return to the XI, Klopp said: "He is in really good shape and if you look at how we came through this now with the last two games winning, we don't see it [his suspension] as a bad thing, the time he was out.
"We used it with him, we tried to give him some extra input physically as well as tactically. He looks really settled now, even more than before, he had a really good last week.
"What we will make of that, you will have to wait until tomorrow."
Everton, meanwhile, will be able to field their trio of recent arrivals in Neal Maupay, Idrissa Gana Gueye and James Garner at Goodison Park.
Frank Lampard has no fresh fitness concerns but continues to be without Abdoulaye Doucoure, Dominic Calvert-Lewin, Mason Holgate, Yerry Mina, Ben Godfrey and Andros Townsend.
Lampard told reporters: "He [Maupay] will be in the squad, for sure; we've talked about the striker situation with Dominic being out. He's come straight into consideration. Gana Gueye will be in the squad.
"It's the case when you're bringing players in and [with] some of them it's been a bit of a process and a bit of time and the lads are not always training at full level... so whether they'll be starting is a question mark, but they'll be in and around it and we'll get them up to speed very quickly."
Last match
Liverpool 2-1 Newcastle United (August 31): Alisson, Alexander-Arnold, Gomez, Van Dijk, Robertson, Fabinho, Henderson, Elliott, Diaz, Salah, Firmino.
Leeds United 1-1 Everton (August 30): Pickford, Patterson, Coady, Tarkowski, Mykolenko, Onana, Davies, Iwobi, McNeil, Gordon, Gray.
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