It's not a matter of position for Yedlin, it's a matter of where his skills fit in a formation. He has pace, he can beat a defender with straight line speed and cross, but little else - at this time. He is not a scoring threat. He is not a dribbler. He is getting better at defense. Good Man defense, but questionable Team defense.
In a 442, his skills fit as a RM - similar to a Lennon-type player. This is where he fits for TeamUSA. In a 4231 that Spurs play, he would need to play as a RB - similar to Rose.