Belgium coach Marc Wilmots says Marouane Fellaini is not being played in his best positions at Manchester United.
Fellaini, 28, has struggled to replicate his Everton form since joining United in a £27.5 million deal when David Moyes took charge of the club in the summer of 2013.
Under Louis van Gaal, the Belgium international has been used as an emergency striker on occasion as well as in his preferred position as a defensive midfielder.
Wilmots, though, says Fellaini is primarily a box-to-box midfielder and that he cannot play in holding midfield if he is expected to share the role with a partner.
"I know him by heart," he told The Times. "In my eyes, he is a box-to-box [midfielder]. He could also play as No. 6 by himself, but not with a partner.
"He has the ability to play on the offensive too, as Everton used him. He is the best goal scorer I have. He is a very good player with a unique profile, but he is a player who must be used taking his qualities into account."
Belgium take on Portugal in Leiria on Tuesday in an international friendly that had originally been scheduled to be held in Brussels, only for the match to be moved in the wake of last week's terror attacks in the Belgian capital.