When Borussia Dortmund plays its decisive UEFA Champions League match against Sevilla on Tuesday, it is likely to do so without Gio Reyna.

Reyna missed Borussia Dortmund’s final training session on Monday ahead of the club’s Round of 16 second leg vs. the visiting Spanish side. The 18-year-old winger did not dress in this past weekend’s 4-2 league loss vs. rival Bayern Munich, and Borussia Dortmund has yet to give a specific reason for his absence.

Reyna, Jaden Sancho and Raphael Guerreiro were all abruptly ruled out of Dortmund’s recent Bundesliga clash with Bayern Munich for undisclosed reasons, and now all three appear set to miss out. Sancho has already been ruled out officially, while neither Reyna or Guerreiro took part in Monday’s training session.

“For Jadon it is a matter of weeks. For Raphael and Gio it is a matter of days,” Dortmund manager Edin Terzic told reporters on Monday. “We do not know if it will be in time for tomorrow. We hope they are fit tomorrow.”

Reyna last suited up for his team on March 2 in DFB-Pokal action, though he was an unused sub in the 1-0 road win over Borussia Moenchengladbach. His most recent on-field appearance came days prior via a 70-minute cameo in a 3-0 German Bundesliga home victory vs. Arminia Bielefeld on Feb. 27. The U.S. Men’s National Team youngster started in that match.

Dortmund will look to uphold its current 3-2 lead earned after a first-leg victory in Sevilla, a match Reyna dressed for, but did not appear in.