Complex sentence: In the swing era of big band music, woodwind players were often expected to play multiple woodwind instruments; saxophonists might be offered gigs where they were also required to play clarinet, for example.
Split into simpler sentences: In the swing big band era, woodwind players were expected to be able to play multiple woodwind instruments. Some jazz saxophonists are offered gigs where they are also required to play clarinet, for example.