Still not sure what point you are trying to make re Morrison, players get loaned out 1. To develop them , get game time and come back a better player 2. Because they are on the fringes of the team, not seen as likely to step up and basically surplus to requirements, loan them out and run down their contract at minimal cost to the club .
I suspect Morrison is option 2 so simple question if SR called him back and put him straight into the 1st team as you suggest, would he be better than Carson or Gillespie?