Anderson was missing from the starting lineup for Friday's game after coming out the previous night against the New York Mets with a lower back strain. Reid Gorecki made his first big league start in left field.
Prado, who is hitting .309 with eight homers and 37 RBIs, could miss the entire three-game series after being diagnosed with "exertional headaches." He's scheduled to meet Monday with Atlanta neurologist Richard Bernstein.
Prado has been out of the lineup since last Saturday. He hopes to avoid the disabled list but doesn't want to risk a relapse. He's being treated with anti-inflammatory medication.