Perhaps it's appropriate that as Addison - once the most hated TV wife in America - mulls her departure from Seattle Grace, a new Grey's Anatomy guest star may spell trouble for Meredith and Derek.

According to E! Online's Kristin Veitch, sources close to Grey's Anatomy report that Chyler Leigh â€" the former Reunion star who plays the woman in the bar we saw in the previews for this week - has just been offered a role in a multiple-episode arc for next season.

Fans no doubt hope that her storyline has something to do with Cristina or Burke or Dr. Bailey or Callie or Izzie or... pretty much anyone but Derek Shepherd.

But if the first few seasons of Grey's Anatomy are any indication, we wouldn't count on it. Even if they belong together, the producers seem to devise new ways to drive Mer and Der apart.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.