In order to keep rights in Joppru (I accept Vinny's comments that the team likes what it sees), the Texans either had to put Joppru on the 53 man roster, or IR him.
If they put him on the 53 man roster, someone else had to be released (and his rights lost), or possibly put on IR (Simmons might have been a candidate, I don't know enough about his medical situation and likelihood of return).
There is no point in putting Joppru on the 53 man roster unless you plan to activate him on the 45 man roster for game day. Again, to add Joppru you have to leave someone off. Also, unless you are a starting QB, you have to play special teams on game day. If they activate Joppru, then how many reps can he get anyway. Don't they still need to give some reps to Miller and Bruener? How many reps can they hope to get from Joppru if he's missed so much time? What about chemistry between Carr and Joppru? Wouldn't it be a little off now (compared to Bruener and Miller) after all the missed time?
As a fan, I'm disappointed, because I'm anxious to see Joppru play, but without an injury to Miller, or Bruener, I think they did the right thing.