Borussia Dortmund youngster Jadon Sancho is expected to be out for "several weeks" after suffering ankle ligament damage in Friday's 3-2 win at Cologne.
Sancho featured as a substitute in Dortmund's 3-2 victory at the RheinEnergie Stadion, replacing Christian Pulisic with 18 minutes to go and playing a key part in Andre Schurrle's winner, brilliantly springing the counterattack which brought about the goal.
The win moved Dortmund into fourth in the Bundesliga table after Matchday 21.
But the tricky winger appeared to turn his ankle in the turf late on and had to make way, leaving Dortmund with 10 men for the final moments due to already making their permitted three changes.
The club confirmed the injury is a significant one Monday, putting out a statement on their website which read: "Borussia Dortmund will be without Jadon Sancho for several weeks.
"An MRI examination conducted in Dortmund on Monday revealed that the 17-year-old forward had suffered a ligament injury in Friday evening's Bundesliga match away to Cologne."
The 17-year-old England youth international has broken into Dortmund's team in recent weeks after a summer €8.7 million move from Manchester City, making three Bundesliga starts since their return from Germany's winter break.
Sancho has previously starred at the youth levels for England. He scored nine goals in 10 games during the U17 UEFA championships, three goals in three games at the U17 World Cup and a goal in three games at the UEFA U19 championships.