Roberts vs. DeRosa alone isn't a huge difference besides Roberts being able to hit lefthanded and speed. On that alone, don't know if it's worth it. However, as was mentioned DeRosa playing 3rd, SS, 1B, and OF 5 out of 6 games in a week might since he seems to be able to play anywhere and you know that he's going to be needed. Not going to get into the leadoff hitter debates.