Trent Alexander-Arnold (virus) and Joel Matip (knee) were not part of the 19-man travelling squad for the Reds’ third match in Group E.
Jürgen Klopp will therefore have to alter the back four that began the 1-1 draw with Manchester United at Old Trafford last weekend.
The boss has been boosted by the return of Mohamed Salah, however, after he was not involved on Sunday.
The Egypt international was named in the squad for the 8pm BST kick-off and his potential availability was described as 'promising' by the manager.
"We have to wait [to see] how he reacts overnight," said Klopp. "We will not go [for] any risk. [On Tuesday] it looked really good, that was important."
Xherdan Shaqiri remains unavailable, Nathaniel Clyne is a long-term absentee, and Ki-Jana Hoever has departed for the FIFA U17 World Cup with the Netherlands.
On the possibility of changes, Klopp said: "We have to change two positions already with Joel and Trent anyway, then let's see what we can do on top of that.
"But it's never [just] for changing, it's always for being best prepared for the next opponent – and that's Genk.
"We wanted to find a team, and I think we found it, which can make life uncomfortable for Genk, that's a very important part of the game."
Genk, meanwhile, will continue to be without defender Neto Borges because of a foot injury.
Usual starting goalkeeper Danny Vukovic has not been included in the Champions League squad after rupturing his Achilles tendon in the summer.
Looking ahead to the game, Genk boss Felice Mazzu said: "If we play with the conviction that we showed against Napoli, I believe we can do something.
"Although I fear that Liverpool are are even better [than Napoli]. Their attackers in particular are so dangerous. Speed, efficiency, scoring ability and then that almost continuous high press."
Standard Liege 1-0 Genk (October 19): Coucke, Maehle, Dewaest, Lucumi, Uronen, Heynen, Berge, Ito, Hagi, Bongonda, Samatta.
Manchester United 1-1 Liverpool (October 20): Alisson, Alexander-Arnold, Matip, Van Dijk, Robertson, Fabinho, Henderson, Wijnaldum, Origi, Mane, Firmino.