The 24-year-old defender was gunned down last week as he refilled his car at a gas station in a northwestern suburb of the city, in the latest incident to shock the crime-ridden nation.
"Police have arrested six suspects for the alleged hijacking and murder," police spokesman Mavela Masondo (SAPS) said.
Authorities have said Fleurs was waiting to be served at a petrol station in his Volkswagen Golf 8 GTI when he was confronted by two men, who ordered him out of the vehicle at gunpoint.
Once he got out of his car, they shot him before driving away in his vehicle.
Masondo said the arrests were made early on Wednesday in Johannesburg southwestern township of Soweto— two days after detectives recovered Fleurs's car.
Investigators believe the suspects are part of a crime syndicate responsible for other car hijackings in Johannesburg's Gauteng province.
"The search for more suspects is continuing," Masondo said.
South Africa suffers from a soaring violent crime rate—a key political issue ahead of general elections in May, with opposition parties pointing to the government's perceived failure.
The country recorded almost 84 murders a day between October and December, according to official figures.
Kaizer Chiefs are one of South Africa's top teams, having won a record 53 domestic trophies.