The article goes into depth about the many functions a baritone saxophone can perform in a big band and gives several very specific examples to illustrate.
“The baritone player must remain aware of his role in the music and changes his role to compliment the music. Often, the baritone is scored as part of the saxophone section, part of the trombone section, doubling the fourth trumpet, or doubling the bass player and bass trombone on bass lines. Even these roles can be broken down more specifically. Within a saxophone section, baritone will sometimes double lead alto in sax solis, sometimes play in unison with the two tenors, and sometimes play a part opposite the rest of the section with a call and response to the altos and tenors. Within a single eight bar phrase, the job can also change from one section to the other and back again.”