The thinking I guess is they want to let House work things out in the majors and they don't project Morales to be the long term 3rd baseman. Morales would have to be added to the 40 man, so for now it would mean dropping someone they thought was worthy of a slot previously. Chaparro is a righty, so that's a likely candidate.
As for 1st, Ortiz is coming off a bit of an injury. Spiked his leg and sat for a bit more than a week, so he probably needs a week or so to get back to forcing any issue. On the MLB club, Garcia has started to hit and his fielding is sort of neutral at 1st. Much better than 1st impression, so I think they are willing to ride with him as long as this is a near-.500 club. Mead looks bad at 1st, but he's also learning the position, and, as last night showed, his ability to play 2nd and 3rd is valuable. Vivas / Tena complicates things, but Tena's hitting and Vivas fields the best of the backup infielders. You probably need to deal one of Garcia / Mead / Tena / Vivas to open things up for Ortiz or Morales.