Gibbs played against West Indies and New Zealand over the past week despite straining a left calf muscle eight days ago while fielding in his team's 67-run defeat by Bangladesh.
But team physiotherapist Shane Jabaar said Gibbs had been in doubt for Saturday's game against New Zealand in Grenada.
"He came through his fitness test for the West Indies game, but the day after the match at practice he did a little too much during a game of frisbee and he had a setback," Jabaar told Reuters on Sunday.
"We didn't say too much about it but he was touch and go for the game against New Zealand."
Gibbs has been one of the more dependable players in South Africa's shaky middle order and captain Graeme Smith will be anxious to have him in the team for Tuesday's match, which they must win to reach the semi-finals.
"He's on complete rest today and he won't do some of the high intensity fielding practice the team will do tomorrow," Jabaar said.
"I'll do specific training with him and we'll see how he goes.
"But, judging from how he has respond to treatment in the past and considering that we have some time, I think he should be fine for Tuesday."
The seven-week World Cup culminates with the final in Barbados on April 28.
