Of central and defensive midfielders that made 20 or more starts last season in the top five leagues, there are 11 who are above average for progressive runs per 90, progressive passes per 90 and defensive duel win percentage. Amrabat is one of them (the others are: Bellingham, Rice, Goretzka, De Jong (surprise, surprise!), Zubimendi, Partey, Fofana, Skhiri, Danilo Pereira, Bentaleb and Rakitić). He has a skillset that is rarely found all at once. As great as Casemiro has been for us, he doesn't carry the ball or pass with enough security for what I think Ten Hag wants from his deepest midfielder in possession, hence the Mainoo (who fits the same profile) experiments before his injury. Amrabat is a high volume and secure passer over short, medium and long range, press resistant and very progressive with both passing and carries. He would be great alongside Casemiro against the better sides and an able deputy in games that we'd expect to dominate possession.