Remember that this move is not final. Changes that occur in the spring don't always hold up after a few weeks of training camp. The promotion of Wand to starting left tackle and the move of Pitts to left guard could be looked at several different ways:
1. The coaches think this is the best lineup.
2. The coaches are rewarding Wand for hard work and improvement.
3. The coaches are trying to light a fire under Milford Brown.
Remember that a lot of lineup changes before the summer are meant as motivational tools. This could just be the coaching staff's way of motivating somebody into doing something. It could be that the staff wants to see how Wand will hold up during exhibition games. If Pitts needs to return to left tackle, he could easily make the adjustment after a couple of preseason games.
I personally think that the coaching staff is making this move because of a combination of all three motives I mentioned above. They see Wand as being the left tackle of the future and would like to see how he would work out, and to see how Pitts would be as a guard. They also want to reward Wand for his hard work by showing confidence in him, and if they end up moving Pitts back to left tackle they will make it clear to Wand that he is the left tackle of the future, just not the present. Also, they want to light a fire under Brown/Weary/Washington to compete for the left guard spot and show that the position isn't a weakness that needs to be addressed by moving Pitts.