In this photo from the fourth season finale of Grey's Anatomy, "Freedom," Callie and Mark have a conversation outside Seattle Grace. What's to come of them?

In this photo from the fourth season finale of Grey's Anatomy, "Freedom," Callie and Mark share a moment outside the hospital. What's to come of these two?

In this photo from the fourth season finale of Grey's Anatomy, "Freedom," Derek, Mark and Richard are seen in a rare scene outside Seattle Grace. Where is it?

In a still shot from "Losing My Mind," from the fourth season of Grey's Anatomy, Izzie and Mark have a serious conversation in the halls of Seattle Grace.

In a still shot from "Losing My Mind," from the fourth season of Grey's Anatomy, Mark and Izzie have a serious conversation at Seattle Grace.

Maybe, and not quite the way you think! Callie Torres, Erica Hahn and Mark Sloan have a conversation in "The Becoming."

Callie Torres and Mark Sloan made some love in the on-call room. But surprisingly, Mark later gave her the cold shoulder.

In this photo from "Piece of My Heart," Dr. Mark Sloan (Eric Dane) enjoys a smile at the expense of his friend Derek Shepherd, who's surrounded by all sorts of women he has complicated histories with.

In this photo from "Piece of My Heart," Dr. Derek Shepherd (Patrick Dempsey) gets clowned on my Dr. Mark Sloan (Eric Dane) for the awkwardness of this elevator ride.

Always a fan favorite, Mark Sloan poses for the camera.

Lexie Grey might be onto something with this new look. But seriously folks - that's a lot of blood Nick lost. The doctors tried in vain to save him but it was a lost cause at the end.

Erica Hahn puts Mark Sloan in his place awfully quickly at Joe's when he tries to act upon his "thing" for her.