I would be surprised if you don't see one or both of Pena and Herrera making a start. I get that they have only just joined and haven't played a game with the team but they will have a full week of training with the squad under their belt and seeing as we have only scored one goal in the last two games, that being an own goal too, I would think they would come into contention, especially as they are both supposedly goal scoring threats....
I think you are right about the youngsters though, its a shame but, for their development, its probably best if they do go out on loan, as long as its to a suitable team etc and they get good game time...