Middlesbrough captain George Boateng could be set to leave for another Barclays Premier League club according to his agent Barry Silkman.Boateng has become a fixture on Teesside since his move from Aston Villa in 2002 and was chosen as Gareth Southgate's successor after he traded the captain's armband for the manager's office at The Riverside. But he was suspended for the 1-0 win over Portsmouth at Fratton Park, with Mohamed Shawky taking the anchor role, and did not return to the side for the 2-0 defeat to Everton on New Year's Day. Fabio Rochemback partnered Julio Arca in the centre in that match, while the Argentinian player was named as skipper on both occasions. Now the Dutchman's agent claims a number of other top-flight sides have made contact about a possible January transfer. Silkman said: 'It could be possible that he may leave. 'I've had three or four clubs phone me to ask about his availability, so it is possible, but I'm not 100% sure yet. 'A lot depends, obviously, on Middlesbrough. If Middlesbrough don't want to sell him he won't be going anywhere. 'If they do want to sell, there will be a few clubs who would like his services,' he told Sky Sports News. Southgate, meanwhile, has been impressed by the emergence of Arca as an on-field leader. The former Sunderland man has only just returned to the first team following medial ligament damage sustained in September, but he has made an impression captaining the side in Boateng's absence. The 26-year-old would now appear to be in pole position if to replace Boateng on a full-time basis if he did leave the club. Southgate said: 'I chose Julio at Portsmouth and the team did well there. I didn't have too many options to freshen things up (against Everton) so I kept with most of that team. 'He's certainly an excellent professional, it's important that he has everybody's respect and he did a very good job in those two games.'