Why? We've already got two left fielders. If LaR doesn't come back, I think there's a better chance that Moore gets the nod at 1B and Morse stays in LF, btw...
I think this is a likely scenario and it's also one of the ones I hope we avoid. A downgrade at first and no improvement at our previously weakest position
Also I think it's a bit generous to call Morse and Moore left fielders. They're first basemen who are blocked by a better first baseman and are stuck in the second least important position in the field as a consequence.