Sabella will give his final performance June 10—long scheduled as the actor's final day.
Bartlett will stay with the show until Sept. 18, at which time he'll begin rehearsals for the upcoming Nathan Lane-Matthew Broderick revival of The Odd Couple.
Rialto neophyte Christina Applegate plays the title role in Sweet Charity. She was Tony-nominated for her performance.
Applegate's other co-stars include the Helen and Nickie of Kyra DaCosta and Janine LaManna.
The creative team for Sweet Charity comprises Walter Bobbie (director), Wayne Cilento (choreographer), Scott Pask (set designer), William Ivey Long (costume design), Brian MacDevitt (lighting designer), Peter Hylenski (sound designer), Gordon Lowry Harrell (music director) and Don Sebesky (orchestrator).