The Spaniard, having claimed the Sir Matt Busby ‘Player of the Year’ award back in May, has only featured sporadically under Mourinho this season, making three starts in total.
He has made a statement to his boss over the last week, however, producing a solid cameo against Southampton before dominating midfield proceedings alongside Nemanja Matic during the 4-1 win over CSKA Moscow.
And Herrera, speaking ahead of the clash with Crystal Palace on Saturday, made it clear to the Portuguese that he was ready to play in a variety of roles.
“I know I can play more forward than them, when we play with three, so I will be there for the manager whenever he needs me,” he said. “Sometimes as number six, sometimes as number eight, sometimes No. 10.”
The case of Herrera tells the story of a wider evolution happening at Old Trafford. Last season, for instance, his role was clear: to hassle opponents at will and win the ball back for Paul Pogba. But how he figures in this current midfield, with Matic effortlessly stamping out onrushing threats through the middle and acting as an even better springboard for attacking movements, remains something of a mystery.
And the 28-year-old, in declaring his readiness to serve as a midfield factotum under Mourinho, clearly knows this. He will have to reinvent his style and, above all, evolve over the next few months.