"Unfortunately there are many injuries at the moment," German Siewert told a news conference ahead of Saturday's league clash at ninth-placed West Ham United.
"Jonathan could be out for two or three more weeks. He had a big impact on his ribs."
Siewert said that Erik Durm is a concern, but Terence Kongolo could train tomorrow and Tommy Smith is back from injury.
"We had 15 healthy players on the training pitch today," the manager said. "We will have a look at the squad in training tomorrow before we choose our team."
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Huddersfield have lost 15 of their past 17 league matches and have only 14 points from 30 games.
"At the moment it's still about the games we have left," Siewert added. "I think it's important to know you cannot just win games with fight but we do have to fight.
"The team has won just four games in a year and there are reasons for it and we have to find solutions. We have to score goals."
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by David Goodman)
