No, it's not Bobby who is returning to Supernatural. At least, not yet or that we know of. But some Sam fans might be pleased about the return of this recurring guest star.
You might have guessed from the photo to the right that Mark Pellegrino will be appearing in an upcoming episode. That's right, folks, Lucifer himself is returning to the show in an upcoming episode (possibly in episode 7.15, although we haven't been able to confirm it yet). In a recent TVLine interview, EP Sera Gamble confirms Pellegrino's return, although she doesn't provide any further details.
As you may recall, Sam experienced some pretty serious hallucinations involving his time in hell in the first two episodes of season 7. Pellegrino appeared as Lucifer earlier this season, trying to convince Sam that he was still stuck in Hell and everything he was experiencing wasn't real. Since then, Sam's after-effects from Hell haven't been touched on a great deal and he's insisting that he's learning to deal with the memories and trauma. We've heard rumblings that his condition would be addressed more fully in the second half of the season.
Well, that certainly seems to be true, since Christine Kilpatrick photographed Mark Pellegrino on Monday in his Lucifer garb having lunch on the Vancouver set of Supernatural. She reports that Jared Padalecki was also on the set, leading us to believe that Sam will once again be having either a flashback from his time in Hell or perhaps another hallucination. Is Sam's insistence that he's "fine" the truth or is the younger Winchester headed for a meltdown? Well, when asked, Warner Bros. gave us a bit of a summary of what EP Sera Gamble has been saying about Lucifer's return: as it turns out, Sam's hallucinations never went away, although he has been using some techniques to go about his day (like pressing the scar). But in an upcoming episode, we'll be seeing Sam's coping techniques through his point of view again.
Misha Collins is also set to return in episode 7.17 and two additional episodes after that.
Don't miss a new episode of Supernatural on Friday, January 13 at 9:00 p.m. ET on The CW. View photos, a trailer and a sneak peek for the upcoming episode.

This just goes to show how amazing this show is. Think about it…how many people read this and thought yay! Lucifer is coming back! This show hires amazing actors and the writing is so good you are excited about the king of hell and the devil himself…
I want to see a break down simply for the drama. I'm sure Sam will be put back together after cracking under the pressure.