Brazilian midfielder Fabio Rochemback has reiterated his desire to leave Middlesbrough and return to Sporting Lisbon during the current transfer window.
The 25-year-old has not been picked by Boro boss Gareth Southgate since mid-November and is frustrated by his lack of first-team chances this term.
Rochemback said: "I desire very much to return to Sporting Lisbon. I am disappointed with the attitude of coach Southgate.
"In the summer he promised me that I would have a lot of opportunities within the team, but this is not happening despite me working each day to my maximum."
Rochemback moved to the Riverside Stadium 18 months ago and has scored three goals in 47 appearances for the Teessiders.