Lock Eben Etzebeth is struggling to overcome a calf injury sustained during training ahead of the Springboks' World Cup opener against Japan on Saturday.
Team doctor Craig Roberts says coach Heyneke Meyer has a fully fit squad to choose from, with the exception of Etzebeth, who could still be available.
"He started running last week and we will progress him this week," Roberts told reporters after the team's arrival in Eastbourne on Sunday.
"A decision on his availability will be made later in the week.
"Otherwise it is up to the coach to select the players he wants for the first game."
The Boks are expected to name a full-strength team as a handful of players return from injury, such as Duane Vermeulen and Foruie du Preez being given a chance to gain match fitness.
"In a way the fact they didn't play was also a blessing, because it also enabled us to really work really hard on their conditioning," said Roberts.
"It is a double-edged sword. Yes, there isn't game time, but you're able to get the conditioning up to speed and the strength work that they needed. So it can be a blessing as well.
"We wouldn't put them on the field if they weren't fit to play. That is the key thing.
"They are here because they are fit to play and they can go. We need to manage their loads, but there are also non-injured players that we need to manage their loads.
"Each individual is on an individual programme.
"Rugby is a collision sport and you are going to pick up injuries," he added.
"For us it is about trying to get the guys on the field and get them performing on the field.
"Only time will tell in terms of the performance on the field, but experienced players return to form is generally quicker than other players and hopefully we can get away with guys coming here with very little game time.
"We need to give them some game time, hopefully we have four pool games and they hopefully go well and we can take them into the second part of the tournament."