Suazo has been sidelined for most of the last three months, first with a shoulder injury and then with a pulled hamstring.
He has played only 90 minutes of competitive football in that time - 45 minutes in a pre-tournament friendly and 45 minutes in Chile's second World Cup group match against Switzerland.
He looked out of form against the Swiss and was substituted at half time. In recent days he has not always figured in Bielsa's starting 11 in training sessions.
Bielsa declined to say whether Suazo would start in Pretoria but gave a typically cryptic answer to a question at his pre-match news conference, suggesting that Suazo was still not match fit.
"The difficulties that he has are related to the fact that for some time he has not played in official matches," the coach said.
"This is something that can be resolved by playing and also by training, but fundamentally by playing proper matches. So it's a difficult situation to resolve. We can't change a training session for an official match."
Bielsa said he would stick to his usual three-pronged attack with two wingers and a striker.
"It could be Suazo, it could be Paredes, it could be Valdivia, who all interpret that role in different ways," he said.
Jorge Valdivia played as a striker in Chile's opening victory against Honduras but with playmaker Matias Fernandez suspended, Valdivia is likely to drop back to play behind the forwards against Spain.
That leaves Esteban Paredes as the most likely replacement for Suazo, who scored 10 of Chile's 32 goals in the qualifying campaign, more than any other player in South America. Paredes came on in the second half against the Swiss and looked sharp.
Chile need only a draw against Spain, who must win to be sure of reaching the knockout stages of the competition.
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