Molina will start Sunday's game in Atlanta, Alex Pavlovic of NBC Sports Bay Area reports.
Molina began the season in the Atlanta organization before the Giants acquired him Aug. 2. After being recalled from Triple-A Sacramento last week, Molina made his team debut in long relief Tuesday, tossing 4.1 scoreless innings in a 3-1 win over the Reds. He tossed 52 pitches in that outing, so Molina could have his workload capped at around 60-to-75 pitches as he makes his third career big-league start and first as a member of the Giants.