The 2012 Lollapalooza lineup isn’t supposed to be formally announced until Wednesday, but a rumored lineup surfaced over the weekend. According to the document, Black Sabbath, the Black Keys, the Red Hot Chili Peppers and Jack White would headline the event.

If the leaked lineup is true, it would signal to a return to Lollapalooza’s hard rock roots. In recent years, pop and hip-hop acts like Lady Gaga, Eminem and Kanye West have earned headlining status, but the most “pop” of this year’s big names would be Florence + the Machine.

Other names appearing on the bill include Passion Pit, the Shins, Bloc Party, Justice, Franz Ferdinand and Metric. Bassnectar, Calvin Harris and Kaskade would headline the Perry’s dance music stage.

Even if the entire rumored lineup is not accurate, some of the names have already been confirmed, via a Lolla-sponsored series of billboards and advertisements around the city of Chicago bearing lyrics from acts on the bill. Jack White, Sigur Ros, M83, Justice, Washed Out and Santigold are among the acts definitely appearing at the fest based on these teaser ads.

Creating fake Lolla lineups has become something of an art form over the years, so there’s no telling whether this one is true. Two reasons to be skeptical: The absence of Garbage, who have been strongly rumored for weeks and have an open date on their touring schedule that would be a perfect fit, and the inclusion of the Chili Peppers, given that they have an arena show in nearby Rosemont on May 28, barely two months before Lollapalooza, which takes place in Chicago’s Grant Park on August 3-5.