The pictorial features Lohan paying homage to late screen icon Marilyn Monroe.
TMZ said Playboy executives are "freaking out" because they fear the leaked images might damage sales of the magazine, which paid the "Freaky Friday" and "Mean Girls" star $1 million to pose for its layout.
The issue, due out next week, is expected to be the magazine's best-selling copy of 2011, the entertainment news Web site said.
Lohan, 25, is on the comeback trail after years of drug addiction and legal troubles stalled her once-bright acting career.
Notable deaths of 2014 [PHOTOS]
Meg Ryan, Kiernan Shipka to star in 'Fan Girl'