The batting allrounder has been named in Boland's squad for the upcoming domestic campaign after being deemed surplus to requirements at Hove
Stiaan van Zyl's spell at Sussex is over and the left-handed batter will resume his career in his native South Africa.
The Hove club have deemed the 33-year-old surplus to requirements ahead of the resumption of their LV=Insurance County Championship campaign.
After overlooking the batting allrounder during their One-Day Cup season, Sussex are choosing to focus on giving experience to young players when the red-ball season resumes later this month.
Youngsters Archie Lenham, Harrison Ward, Dan Ibrahim, Oliver Carter, James Coles, Alistair Orr and Jack Sarro have all earned outings this season for the south coast club.
Van Zyl will return to South Africa after four seasons at Sussex having been named in Boland's squad for the upcoming domestic season.
"As my time comes to an end at Sussex, I want to thank everyone at the club and all supporters for the last five years," said Van Zyl, who made 61 appearances across all formats.
"I'm extremely proud and grateful for the opportunity given to me to represent Sussex. I made some great friends and memories over the years.
"Unfortunately, my time at Sussex didn't end as I would've liked competing for a trophy, but I wish the club all the best for the rest of the season and the future."
Performance director Keith Greenfield added of Van Zyl, who has played a dozen Tests for The Proteas: "Stiaan has not had the season he and we had hoped for, and the COVID-19 pandemic and his knee injury has made the last couple of years very tricky.
"Despite that, he has always given his best and is a top man who has been great to have around over the last five years. We wish him well for his future back in South Africa."