According to Rumour Fix, the 18-year-old will take part in an photo shoot in Los Angeles for an upcoming issue of the men's magazine.
Mercede's possible Playboy layout follows nearly a year after brother Levi posed nude for Playgirl.
It is thought that Levi's sibling has prepared for the photoshoot by shedding more than ten pounds.
Last summer, Mercede expressed doubts about the stability her brother's reconciliation with Bristol Palin. Palin and Johnston later ended their relationship.