The United skipper has been named in the starting 11 for the derby at the Etihad Stadium this afternoon after missing three games through suspension.
"For me it is not a hard decision. Rooney is my captain and I put him back in because he gives us more strength to the midfield," Van Gaal told Sky Sports News.
"We play more or less like our philosophy. It is always the same, we want to dominate possession and create chances. We have to take in account the quality of Manchester City.
"They have been champions two of the last three years, and I have made my plans for my players."
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