The Brazil international has missed three matches with a shoulder injury but has returned to light training and could potentially make a return ahead of schedule.
Klopp is also waiting fitness updates on midfielders Thiago Alcantara (knee), Naby Keita and centre-back Joel Matip (both of whom had minor knocks) as all missed the midweek Champions League victory over Ajax.
Record signing Rhian Brewster could make his full debut for Sheffield United against his former club.
The 20-year-old striker, who joined the Blades earlier this month in a deal that could be worth up to £23million, made his first appearance for Chris Wilder's side as a second-half substitute in the draw with Fulham.
Max Lowe had to be withdrawn with a head injury in that game and the Blades are awaiting a doctor's report before deciding if he travels to Merseyside. Meanwhile, after the 1-1 draw with the Cottagers, Wilder revealed that midfielder John Fleck will be out for up to six weeks with a back problem.
Liverpool provisional squad: Adrian, Alexander-Arnold, Gomez, Matip, Robertson, Fabinho, Henderson, Keita, Salah, Firmino, Mane, Kelleher, N Williams, R Williams, Milner, Shaqiri, Jones, Minamino, Jota, Origi.
Sheffield United provisional squad: Ramsdale, Foderingham, Baldock, Stevens, Basham, Lowe, Robinson, Bogle, Jagielka, Ampadu, Lundstram, Norwood, Berge, Osborn, McBurnie, Sharp, McGoldrick, Burke, Brewster.