"Yesterday" is the eighteenth episode of the second season of Grey's Anatomy and the 27th produced episode of the series. It is also the 27th produced episode of the Grey's Anatomy franchise. It was broadcast on February 19, 2006.
Mark Sloan arrives in Seattle to try and convince Addison to leave Derek and return to him and her life in New York while his presence causes tensions for Derek who is forced to work with his old friend. Burke and Cristina's relationship is tested when one of her secrets is revealed while Meredith is forced to unearth truths about her past and her parents divorce. George debates whether to tell Meredith and how he feel and Izzie stands defiant that she won't sleep with Alex again.
- "After careful consideration and many sleepless nights here's what I decided: there's no such thing as a grown up. We move on, we move out, we move away from our families and form our own. But the basic insecuirites, the basic fears and all those old wounds grow up with us. And just when we think life and circumstance have forced us to truly, one and for all, become an adult you're mother says something like that. Or worse, something like that. We get bigger, we get taller, we get older but for the most part we're still a bunch of kids running around the playground trying desperatly to fit in."
- "I've heard that it's possible to grow up, I've just never met anyone whose actually done it. Without parents to defy we break the rules that we make for ourselves. We throw tantrums when things don't go our way. We whisper secrets with out best friends in the dark. We look for comfort were we can find it and we hope, against all logic, against all experience. Like children, we never give up hope."
- "Diplo Rhythm" - Diplo
- "Nightrocker" - The Chalets
- "Just One Breath" - Devics
- "Closer" - Joshua Radin
- "It Don't Matter To The Sun" - Rosie Thomas
- "Everybody Needs A Fence To Lean On" - Headlights
- "Like A Star" - Corrine Bailey Rae
This episodes' title references the song Yesterday, originally sung by The Beatles
- This episode marks the first appearance of Mark Sloan