Manchester United boss Louis van Gaal admits a new central midfielder is a priority for the summer market.
Van Gaal is seeking competition for Michael Carrick.
"No.6 is a key player, yes. I have more key roles - the no.6 is just one of those key roles. You have seen this season, for example, because Michael Carrick is injured and I don't have another, I have to play with Ander Herrera there. He did it very well, but it is not his specialty.
"I have played Wayne Rooney there also, but it is not his favoured position. I had to do this because I don't have another right-footed holding midfielder like Carrick. That is why it is a key role, but I cannot discuss other positions because then I show too much."