Question about Odoms

After hearing that Odoms got moved to the outside WR position, I was wondering why this move was made. I always thought slots were the smaller, shiftier guys that attack the middle of the field and the outside guys were taller and stretch the field more. Was this move made because he's been one of our more reliable pass-catchers, is it because of lack of numbers, or what? It's not that I have any problem with the move, I've just been curious as to why it was made.