I've just been remining myself of his last Sassuolo season. They played most of the campaign in a 4-3-3 formation and Frattesi would play as the left sided of the two more advanced midfielders, ahead of Maxine Lopez and alongside Mattheus Enrique or Kristian Thorstvedt. So sort of where Miki plays now. It's needed him to adapt to a different formation, but the midfield trio part is hardly new for him.
He had the 7th most touches over the season and the second highest in midfield after the anchor Maxine Lopez. All his creative and attacking stats are among the best in the squad and, most unusually, he won more tackles than any other player - 63, which is 50% more than any teammate. Weird. He had the third highest minutes played over the season so perhaps it is just a case of him needing more regular football. Perhaps.