The Belgian international was acquired on transfer deadline day and his arrival means there will be extra competition for places in the United midfield.
But Carrick is happy about the deal, telling the Manchester Evening News: "It's something I welcome.
"The more top quality players you have in your squad, whether it's in my position or not, the better it is for the team.
"It's not a case of me thinking 'I might not be in the team'. I will have to play well to be in it, regardless."
Carrick was hugely impressive for United in their title-winning campaign last term and added: "I can't deny last season probably was my best one. My form was good and I was consistent.
"But it wasn't like I suddenly jumped from one level to the next. I didn't do anything differently to what I had done in the years before."