The 25-year-old has been plagued by fitness issues this season. His latest setback came in only his second game since returning from a knee ligament injury suffered in December.
"He worked hard to return from the injury he suffered before Christmas but after his first start he is injured again," Wagner told a news conference ahead of Saturday's league match at 13th-placed Brighton & Hove Albion.
"He'll have surgery on Monday and will be back for the start of pre-season."
Promoted Huddersfield are 16th in the table and battling to avoid a return to the Championship. They have 31 points from 32 games and sit three points above the relegation zone.
"I'm confident we have everything to stay up," Wagner added. "Even if it will be difficult. Getting promoted was like a fairytale, staying up would be a miracle."
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Christian Radnedge)
