Niko Kovac says long-serving attacker Arjen Robben deserves better than to spend the final months of his Bayern Munich career on the treatment table.
Veteran winger Robben, 35, fears he has played his final game for the club after a hurting his calf in the latest of a long series of injury issues.
The ex-Netherlands international will leave the Allianz Arena when his contract expires at the end of the campaign.
Robben last featured for the Bundesliga champions on November 27, scoring twice in a Champions League win over Benfica.
"It's very sad that Arjen has not been with us since November," Kovac said.
"He always feels something, even though the doctors are giving positive signs. He just does not feel right at the moment.
"It would be nice if he could play again for Bayern. He deserves that."
Franck Ribery will also miss Sunday's match at Fortuna Dusseldorf through illness, although Alphonso Davies has overcome a knee issue.
Corentin Tolisso is back in training after tearing his anterior cruciate ligament in September and Kovac quelled concerns that the midfielder sustained a setback when he collided with a team-mate during Wednesday's session.
"[Tolisso] didn't sustain an injury in training, but he thought he did," the Bayern boss said.
"It's normal for a player to be more cautious after such a long time out. We have to gradually reintroduce him to the first team."
The Bavarians head to Dusseldorf with a one-point lead at the top of the table following last weekend's 5-0 thumping of Borussia Dortmund.