Sunderland have signed Inter Milan midfielder Sulley Muntari on loan until the end of the season.Muntari, 26, played for Portsmouth in the Premier League during the 2007-08 season before moving to Inter.The Ghana international won the treble of the Italian Serie A, Coppa Italia and Champions League under ex-Chelsea manager Jose Mourinho last season.But he has struggled to secure first-team football at the San Siro since then and handed in a transfer request.He was out of favour under Rafael Benitez at the start of the season and has failed to convince new manager Leonardo of his worth, making only one Serie A start this term.Muntari joins international team-mates Asamoah Gyan and John Mensah at the Stadium of Light.He will not play in Tuesday's home game against Chelsea, but is expected to be available for next Saturday's trip to Stoke.Source: BBC