I have Todd Frazier & Daniel Murphy who could fill-in at 3rd base. For Outfielders I have Carlos Gomez, Melky Cabrera & Austin Davis.
With Harper I would probably get an upgrade in the OF, as he seems to be a more consistent hitter than Bruce. However, I strongly believe that Arenado can be the top 3B this year and who knows how Chris Davis will perform this year..
What do you guys think?