MUNICH (AP) — Just days after returning from a long-term injury break, Bayern Munich midfielder Thiago Alcantara requires another operation after reinjuring the ligaments in his right knee.

The Bundesliga champion says Thiago partially tore the ligaments in practice on Tuesday. The Spaniard returned to team practice last week, and faces another lengthy recovery.

Thiago says he is "deeply disappointed and desperate," but promises "not to give up and to keep on fighting" for a comeback.

He was injured in March and returned to training in May, only to suffer a setback and require surgery on his right knee that ruled him out of the World Cup.