The San Francisco LGBT Community Center took it over in 2015 with financial help from the city.
But the organization is not in a position to continue putting the event on, Wiener said, and no one else has come forward.
"No other community groups have expressed interest in taking over this large street party, " Wiener said in an emailed statement. "As a result, there won't be a street closure this year."
Daniel Bergerac, president of the Castro Merchants association, expressed sadness about the news.
"It's definitely the sign of an end of an era of a very community-focused Castro," Bergerac said in an interview. "To produce an event like this really requires a big labor of love and a lot of time and a lot of effort and a lot of people, and clearly those people just aren't here any more."
At the same time, many Castro residents have called for Pink Saturday to be canceled, Bergarac said.
"It's almost a victim of its own success," he said. "It just got so big and so popular and very hard to control, and for a lot of people it was a scary event."
Wiener says the city still expects a large number of people to be in the neighborhood that night (June 25), and officials are working on a plan to make sure the area is safe and clean "with access to portable bathrooms."
The neighborhood's merchants are also expecting crowds, even though there's no organized party.
"I think people in the Bay Area are genetically programmed to come to the Castro the Saturday before Pride," Bergerac said, noting that after the city canceled the annual Halloween party in the neighborhood, people still celebrated in the area.
The Sisters of Perpetual Indulgence had organized Pink Saturday since 1995.
But in recent years it had trouble paying for security costs associated with the event after a number of violent incidents. In one case, a member of the group was attacked, along with his husband, by people who shouted homophobic slurs at them.
Bergarac says that over time the Castro has undergone a big change.
"It's gone from a predominantly gay neighborhood to now being a predominantly mixed neighborhood," he said, adding that the ties to pride events are not as strong as they used to be.
"Gay men are welcomed in Hayes Valley and Pacific Heights and the Marina as much as they are welcome in the Castro, and that wasn't always the case," Bergerac said. "We're not clustered into our own little ghettos anymore.
"The sad part is, for men my age and older, we sort of reminisce about that time when there was that tight-knit community, when we needed that community."