The former Athletic Bilbao midfielder insists he is ready to make a name for himself at Old Trafford.
"I will miss friends and family," he said. "But I think I'm ready for this big step. I'm ready for this time.
"I am 24 years old and this is the moment to come to the biggest club in the world.
"I come here to be a good professional but there are other players in midfield. Between us I am sure we will help the team.
"But it's not only me. There are a lot of midfielders. They can play well, too."
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