South Africa head coach Jacques Nienaber is hopeful captain Siya Kolisi will feature in their World Cup warm-up match against Wales on 19 August.
Nienaber is also positive on the progress of fly-half Handre Pollard.
"We didn't think they would make the Rugby Championship but after that in the warm-up games then hopefully," Nienaber said about their return.
Kolisi, 32, partially tore the anterior cruciate ligament in his right knee in April playing for URC side Sharks.
Nienaber added: "With rehab you start a process or a rehab programme, let's say there is swelling or a loss of range or movement, you probably go a step back.
"If everything goes well then hopefully they will make the warm-up game against Wales but again I reiterate when I say hopefully - you can't predict."
Springboks team doctor Jerome Mampane said in May it was "too early to make any reliable forecasts on when Kolisi may be able to return to play" amid doubts over his World Cup availability.
Pollard, who kicked 18 points in South Africa's 2019 World Cup final victory over England, injured his calf when playing for Leicester in the Premiership semi-final against Sale Sharks.
South Africa's final game before the World Cup is against New Zealand on 25 August at London Stadium.
The Rugby World Cup will then take place in France from 8 September to 28 October.
Head coach Nienaber concluded: "One thing I will definitely tell you is that we will not push them or force them to play if they aren't medically right and confident.
"Confidence is something they will try and get out of training sessions and then they will probably have to build their confidence in games. But hopefully we can get them back but it will be what it will be."