The 26-year-old emerged as a target for Jurgen Klopp's side following Wednesday night's 2-1 win over Newcastle United, which saw captain Jordan Henderson pick up a hamstring injury.
With Thiago Alcantara, Naby Keita and Alex Oxlade-Chamberlain also sidelined, and Curtis Jones only just returning from injury, Liverpool's shortage of midfield options has compelled them into a deadline day move.
Talks over a loan deal for Arthur have progressed quickly, and transfer expert Fabrizio Romano reports that the signing is now close to being completed after all parties agreed terms.
The Brazil international will now fly to the UK and undergo a medical this afternoon before the expected confirmation of his arrival before Thursday's 11pm deadline.
The loan agreement does not include an obligation or option for Liverpool to buy Arthur on a permanent basis at the end of the season.
Arthur has found playing time relatively scarce since his switch to Juventus from Barcelona, making only 31 appearances across all competitions for the Italian giants last season.
The midfielder is yet to play at all this season, although he could still be ready to make his debut for Liverpool during Saturday's Merseyside derby against Everton.
Liverpool will go into that match looking for a third successive Premier League win, having opened the campaign by taking just two points from their first three outings.