A decision on strike bowler Dale Steyn's participation in the opening match of the Champions Trophy on Thursday will only be made just before South Africa face India in Cardiff, Cricket South Africa said on Wednesday.
Steyn, seen as key to his team's chances, has been diagnosed with a mild left side strain, having complained of tightness during South Africa's warm-up loss to Pakistan on Monday.
"Dale Steyn remains doubtful for the match, with a decision on his availability to be made early on Thursday as he continues to receive intensive treatment," said a statement.
Captain AB de Villiers, speaking at a news conference in Cardiff, suggested the team might err on the side of caution.
"It's not looking good, but we'll just reassess and make a final call. It's sort of touch and go, but it is, obviously, an issue and something we'll have to look at. There are a few more games coming up so we wouldn't want him out of the rest of the tournament."
The captain said South Africa were confident despite the poor performance in the six-wicket defeat by Pakistan.
"We come here as a tough team," De Villiers said.
"Mentally we feel ready and we feel strong. I think the other thing that is very good is to have walked into a very good Pakistan team on a wicket that did a bit in the morning. All of the bowlers had a nice work through, it was really good.
"It's not a bad thing to lose those warm-up games," he added. "It's a bit of a wake-up call; it reminds us that this is the time to go. We're in the big tournament now. There is no more room for error."
South Africa play Pakistan on Monday at Edgbaston and West Indies back in Cardiff in their other Group B matches with the top two going through to the semi-finals.