Whilst I think this a dangerously poor selection, I'm totally unsurprised by it given SC's comments.
He clearly doesn't rate Maloney, and is shoehorning Osborne into the side following El Abd's arrival. I think it's likely El Abd would have been basically guaranteed First Team football.
Reid can't play two games in a week, so is "rested".
W.Elliott is 35 and likely can't play two games in a week, so is saved for Saturday when he'll have trained with our squad a bit.
M.Elliott and Pack are selected to "toughen us up" in midfield a little bit. I don't think it will work personally, but I reckon that's the theory. For what it's worth I think Marv gets a bit of unfair stick from some. He'll be energetic and break up or disrupt their play, although we all know he can't really pass for toffee.
i don't think JET being left out is anything other than being rested, as others have said, if a serious bid had come in he wouldn't be in the squad. We'll miss his creativity/goals/assists and the space he creates for others.
I think the whole selection is SC trying to make us a little more physical, which of course has meant we'll sacrifice creativity. Set pieces are our best bet for a goal.