In the 2023/24 season, Castillo played 32 games for Amakhosi across all competitions with a return of five goals and two assists.
However, despite his exploits from deep in midfield, the club finished 10th in the Premier Soccer League, their worst finish in PSL's history.
When the Venezuela international thought he would have a better second year under new coach Nasreddine Nabi, he ended up missing a big chunk of the season owing to injury.
He ended up playing just nine games with a single assist to his name, but that wasn't enough to keep him at the club, according to his agency.