Harold Perrineau returning to LOST

I'm a little late on this, but Harold Perrineau ( Michael ) will be returning to his role next season on LOST. ( link )

This brings up a lot of interesting possibilities. I wonder if that means he's in flashbacks? Or if he and possibly Walt are going to come skipping back to the island? Or maybe there's some "post island" stuff we'll see much like in the season finale.

So many more questions...