KFOG will stop airing its current format and its call letters will vanish next week.
Its signal, 104.5, will start broadcasting KNBR 680's sports programming beginning Sept. 6.
The Chronicle reports KFOG's ratings dipped after its owner, Cumulus Media, sold KFOG's sister station that simulcast in the South Bay.
KFOG's origins as a rock station date back to 1982. It held an annual outdoor concert and fireworks show in San Francisco from 1994 to 2010 called KaBoom, which drew more than 350,000 people.