Sancho played on the left with Rashford on the right vs Arsenal. That is the most impressive outing of Carrick's 3 game in charge.
Recall Bruno goal to made it 1-1 and you should recall where Sancho played. That certainly leave the impression of his better position, especially when the most recently Sancho played more on the left with Dortmund.
Chelsea game despite the goal, he was pretty tame for most of his minutes. The Villarreal game was even worse where there was no creavity from our team until Ronaldo broke the deadlock of a boring, uninspiring game, which forced Villarreal to come out at the end trying to get the result. Only if you only look at his goals, then you would think Sancho was better in Villarreal and Chelsea games in comparison to Arsenal game
His best games worthy of MOTH for us came under Ragnick.
You can't blame RR to pick up where Carrick left. Carrick had been with this team for so long, after having the authority to try thing in these 3 games, ended up with conclusion to play Sancho on the left wing.
Edit: I think Rashford provided an assist from the right to Ronaldo in this Arsenal game, also cement the impression about the best position for our attackers.