United used the summer to change the centre of the pitch. Carlos Baleba arrived from Brighton, while Youri Tielemans and Andrey Santos added further competition.
Baleba supplies the athleticism that has often been missing. He can cover ground, win duels and carry the ball through pressure. An injury delayed his introduction, which has prevented Carrick from immediately using the midfield balance he planned.
Tielemans can alter the direction of a move with one long pass and already understands the pace of this league. Andrey Santos is younger and more mobile, capable of protecting the back line or stepping forward as an eight.
They join Fernandes, Mainoo, Mount, Casemiro and Manuel Ugarte. Carrick therefore has options, but options are not the same as a functioning unit. He needs a combination that protects the defence without leaving the attack disconnected.
The running concerns increase the importance of this area. If the midfield neither controls the ball nor wins it back quickly, United can look like two separate teams.