Manchester United midfielder Anderson will be out of action until February with a knee injury, manager Sir Alex Ferguson has confirmed.
The Brazilian, 23, has travelled to Portugal to see the same specialist who performed an operation on a damaged cruciate ligament two years ago.
Anderson has not played since the European match against Otelul Galati on 2 November because of the knee injury.
Ferguson described the latest development as "not good news".
With Tom Cleverley sidelined until Christmas, Anderson's unavailability leaves United light in midfield during an important stage of the season as they look to close the five-point gap between themselves and Premier League leaders Manchester City.
Ferguson, though, is ruling out bringing in reinforcements in January.
"It is easy to say you are going to buy players but it is not easy to buy them for Manchester United, especially in January," he said.
"I do not see anyone who could make us a better team.
"There are two or three players but they are not available, so there is no point even going there."
One bit of good news for Ferguson on the injury front is that striker Wayne Rooney, who has played in midfield in recent weeks, is fit again after he missed the 2-2 Champions League draw with Benfica last Tuesday.