Stewart is unable to appear due to scheduling conflicts.
Grammer previously performed the role in concert in 2007 with the New York Philharmonic.
He will be playing opposite Alexandra Silber as Eliza Doolittle. Silber will also play opposite Nathan Gunn in selections from South Pacific and Carousel.
Grammer, well known for his portrayal of Dr. Frasier Crane on "Cheers" and "Frasier," earned a Tony nomination for his 2010 performance as Georges in La Cage aux Folles.
For more information, visit SFSymphony.org.