The Spain international penned a four-year deal at the Red Devils last month after completing a £29m switch from Athletic Bilbao to Old Trafford.
I think he’s going to be a key player for Manchester United
Herrera, who was a target for ex-United manager David Moyes last summer, scored five goals and made five assists in 33 La Liga appearances last term.
And Scotland midfielder Fletcher believes Herrera is settling quickly into life at the 20-time English champions.
“He’s a really talented footballer,” Fletcher said.
“He’s settled in really well and not only with the other Spanish-speaking lads. I think he’s going to be a key player for Manchester United.
“He has great enthusiasm and great energy in midfield. He always wants the ball and is always looking to make things happen.
“His enthusiasm’s infectious – it’s rubbed off on a few of us already – and he works hard for the team. He wants to learn and listen, he takes on instructions well… and off the pitch he’s a good lad.”
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