Raiders GM Reggie McKenzie granted a quick interview with Jerry McDonald of the Contra Costa Times after Stanford's pro day. You can see a transcript of the interview here.
He addressed a number of different issues in the interview. I encourage you to check it out, it's an interesting read. But we will sum up the conversation as well.
First, McKenzie confirmed that second year player Stefen Wisniewski will indeed be moving to Center. The only reason that wouldn't occur is if they find themselves in a position where they can get another Center that is so good they can't pass him up. That could happen in the draft or if there is an unexpected cut at a later date.