The 30 Rock actor boarded the project back in March, taking on the role of titular club owner Dennis Dupree.
However, according to The Hollywood Reporter, Baldwin has since decided against appearing in the Adam Shankman-directed project for unknown reasons.
The ensemble Rock of Ages cast includes Malin Akerman, Bryan Cranston, Catherine Zeta-Jones and Russell Brand.
Baldwin recently signed on to appear in a currently untitled Woody Allen film due to begin shooting in Rome later this year.
He previously dropped out of Men in Black III, citing scheduling conflicts as the reason behind his decision.