With this individual? Lower. If they don't consider him a left fielder than they would obviously rank him lower if he were playing left field.
If you mean what would he rank if he was proven to be an average left fielder? Higher, but not at the truly elite level of prospect. SG is correct when he says that after a few choice names at the top a lot of the list is pretty interchangeable.
With his plate discipline issues his bat is going to have to be really good to provide a lot of value at 1B/DH. I hope he keeps his above average footspeed and can gain a bit of value with smart baserunning.