I can't see Tello getting much success on the right. He doesn't have the option of coming inside on his left so becomes too predictable. He has pace but his close control isn't so good so can't generate unpredictability with trickery and dribbling. He needs to be played on the left. But downgrading Neymar to the right for Tello on the left is a valid option. Only way I could see it working is Tello on the left with Messi on the right and Neymar as false 9. Otherwise Tello only would be useful for rotating with Neymar occasionally.