Juan Bernat is set to miss the majority of the season after Paris Saint-Germain confirmed the full-back has suffered an anterior cruciate ligament injury.
Bernat had to be helped off the pitch by PSG's medical staff after hurting his left knee late on in Wednesday's 1-0 Ligue 1 victory over Metz.
The former Bayern Munich full-back went off in the 86th minute, having only come on as a substitute in the 63rd minute, before Julian Draxler's stoppage-time goal sealed PSG's first victory of the season.
PSG have now revealed Bernat sustained an "isolated rupture of the anterior cruciate ligament", with a further update to be provided in the following days.
While no timetable for his return was announced by PSG, early reports suggest Bernat could be facing six months on the sidelines.
Bernat's injury comes as a further blow to Thomas Tuchel, who was without suspended trio Neymar, Leandro Paredes and Layvin Kurzawa, and the injured Thilo Kehrer and Marco Verratti – who has returned to individual training. Kylian Mbappe is also yet to feature this season after testing positive for coronavirus, while Alessandro Florenzi's fitness is being monitored.
Marquinhos and Mauro Icardi, however, played all 90 minutes after returning from periods of quarantine after they contracted COVID-19.