Marston Hefner's Alleged Victim Claire Sinclair -- I'm QUITTING Playboy ... For Now

The Playmate who was allegedly kicked and beaten by Hugh Hefner's son Marston is disassociating herself from Playboy ... at least for the foreseeable future -- TMZ has learned.

Sources close to 20-year-old Claire Sinclair tell us, the model has canceled all future Playboy-related appearances, events, and photoshoots pending the outcome of her domestic violence case with Marston.

Claire has even lawyered up with powerhouse attorney Keith Davidson -- who tells us, "We are taking this matter extremely seriously and we are completing a thorough investigation into this situation."

TMZ broke the story ... 21-year-old Marston was arrested Sunday night after allegedly kicking and punching Sinclair during an argument in their Pasadena, CA apartment.