Plymouth hope to complement the loan signing of West Ham defender Bondz N'Gala with the arrival of Zimbabwe full-back Onismor Bhasera.
The Pilgrims' head coach Paul Mariner has identified defensive reinforcements as the key to helping an increasingly difficult fight against Championship relegation.
Tuesday's 2-0 defeat to QPR left Plymouth firmly in the drop zone and centre-back N'Gala will now arrive from West Ham on Thursday, while efforts are under way to secure a work permit for Bhasera.
Mariner told the club's official website: "N'Gala's a very, very strong defender.
"He's not an archetypal Championship defender, he's got more ability than that, but he's an uncompromising defender who likes to defend.
"He's been on our radar. He came in for a week's training and we wanted to keep him but it wasn't happening.
"West Ham had some injuries but now they've got players coming back they have lent him to us. We're very grateful.
"He's a very intelligent player and a quick learner. The important thing is he likes to defend.
"It bothers him when either a) the team he's on concedes a goal or b) he gets beat, which is not very often to be honest."