Rumor has it that Terminator: The Sarah Connor Chronicles home-wrecker Leven Rambin will play Mark Sloan’s (Eric Dane) long-lost daughter on Grey’s Anatomy. But that still remains to be seen. What we can assure you, though, is this: whatever role she plays, it’s not going to be good news for Mark and Lexie (Chyler Leigh). Grey’s Anatomy executive producer Shonda Rhimes said so herself.

“I’m not sure it’s the kind of obstacle people are expecting, but it’s definitely a new one. I’m not sure they’ll stick together through it,” she tells Entertainment Weekly.