Middlesbrough boss Gareth Southgate admits Julio Arca may need new ankle surgery.
The midfielder has returned to Argentina to have the injury inspected by the specialist who helped sort out his knee problem last season.
Southgate said: "We have sent Julio to see the medical people in Argentina. We want to avoid another operation because it means that he will be out for a further spell. But if it is going to happen we have to make the decision over the next week."