Having returned to Bayern from an ill-fated loan with Swansea last summer, the midfielder hoped to get his career in Germany off the ground in his second year in the Bundesliga.
However, after a promising beginning to the domestic season with six starts in the first 12 matches, he has come off the bench only five times in the league since.
"I am not happy here," he told Kicker. "I work a lot, but I am not allowed to play."
In 2019, he has only spent 50 minutes on the pitch in five matches across all competitions and the Portuguese midfielder has now voiced his frustration.
"I want to play more, maybe at another club," he said. "I must give thought to this now."