pretty much, and I think that's to be expected. Moving from SS to 3B is more natural than moving from SS to catcher, and moving from CF/LF to RF is more natural than moving to the infield.
If you have a stud SS in AAA knocking on the door and your 3B goes down you don't bring up the fringe 3B in AAA and let the stud rot.
They do have a problem here, and they should have addressed this in the offseason. It's odd that Campbell was the guy they gave the nod to on day one, and left the most MLB ready of the big three in AAA for 2 months.
They will be faced with the decision of trading Abreu or Duran soon, and they probably should have made that move this past offseason. There is such a thing as overplaying your hand. The good news is, the future is bright....again again again.