In the interview we posted earlier, guest star Eric Stoltz said his prisoner character, William Dunn, will be the source of some MerDer drama beginning this week.
TV Guide backs that theory up in its Q&A session today, indicating that what has been a season free of MerDer strife so far may soon take a different turn:
Q: Got any scoop on Grey's Anatomy's Meredith and Derek? Do you have any idea when we'll see the McMansion being built?
A: In lieu of talking drywall (there's no foreseeable movement on Derek and Meredith's dream home, unfortunately), may I interest you in some drama? It turns out that the death row inmate who is admitted to Seattle Grace this week could do some damage to your MerDer. Guest star Eric Stoltz teases that during his three-episode arc, "I certainly insinuate myself into their relationship and am the source of not a little strife."