Jose Mourinho has told Sky Sports it was an "easy" decision to allow Wayne Rooney to leave Manchester United in the summer.
Rooney, 31, returns to Old Trafford on Sunday for the first time since rejoining Everton.
He left United as the club's record goal scorer, and won a host of honours including five Premier League titles and the Champions League.
But Mourinho said he could not block Rooney returning to his boyhood club, saying: "I think it is easy. That way it is easy because you don't have to think a lot.
"You just have to respect the player's desire, and what they decide. And when they're a legend they deserve that freedom of choice."
United face Everton hoping to stay top of the Premier League table.
Much has been made of Mourinho's knack of winning the title in second seasons -- he has done so at Porto, Inter Milan, Real Madrid and during both his spells at Chelsea -- but the coach said that meant nothing.
He added: "I don't know why people speak of the second season because I won in the first season and I won in the third season. I don't really understand it.
"I just think that the second season is a good season for evolution in relation to the first season.
"You have better conditions to work and get those results. But you are playing against other teams whose managers are in the third or second or fourth or fifth seasons. So second may not be a big advantage."