Schalke 04 announced Tuesday that Japan right-back Atsuto Uchida is set to miss the rest of the season having flown home to be treated for a persistent knee injury.

The 27-year-old, who still has two years left on his contract in Gelsenkirchen, has not made a single appearance for Schalke this season and last played in the Bundesliga almost exactly a year ago.

He underwent an operation on his right knee in Japan before the start of the current season against the wishes of Schalke's medical staff.

"He frequently tried to return to training, but he was never 100 percent," said Schalke coach Andre Breitenreiter.

"That is why the medical staff decided to send him back to Japan to see his surgeon.

"From what I have heard, he will stay there for the next few weeks.

"It is important that the boy is completely healthy again and ignores any recommendations to return to training too early.

"The fact is that he won't play a role again this season due to his injury history."

Schalke are seventh in the Bundesliga ahead of Wednesday night's league match at home to mid-table Hamburg.

The Royal Blues are winless in their last five games including their Europa League exit in the Round of 32 after a 3-0 defeat at home to Shakhtar Donetsk last Thursday having been held to a goalless draw in Ukraine.