I think it was someone's idea of getting them both on the field at once, and outside of firstbase, everyone assumes second base is pretty easy to play (which it really isn't if you want to be a good defender).
I like Lucroy alot. I think his batting will come down from where he started last year. He's a great hitter for a catcher. But if you move him elsewhere, he just becomes a solid hitter. Where he really has his most value is behind the plate. If we were considering moving him positions, I would be pissed. He has more value as a catcher than anywhere else. If we really would prefer Martin behind the plate, then we should trade Lucroy to someone else who needs a catcher. The player we get in that trade would be more valuable than Lucroy the second baseman in my mind.