Tottenham defender Danny Rose left the BayArena wearing a protective boot following Tuesday night's 0-0 draw with Bayer Leverkusen.
The full-back played 90 minutes as Mauricio Pochettino's side kept their hopes of progressing to the knock-out stages of the Champions League alive with a valuable point.
Rose was spotted by Standard Sport's Simon Johnson limping away from the BayArena with a protective boot on his foot, although the defender said he was "OK".
The boot may have been used by Rose as a precautionary measure and the extent of the damage the full back has sustained - if any - remains unclear at this stage.
Concerns over Rose will come as a blow to the north Londoners, who have already had to make do without the England international's services for a significant chunk of the campaign due to a hamstring problem.
The 26-year-old only returned to fitness earlier this month after picking up an injury while on international duty with England back in September, and another spell on the sidelines during a flurry of difficult fixtures would be far from ideal.
Ben Davies has proven himself to be a capable deputy but Rose is one of Pochettino's most trusted lieutenants and is a key member of Tottenham's defence, which remains the strongest in England's top tier this term.
Bayer Leverkusen vs Tottenham
Meanwhile, Pochettino has delivered a positive update on the knee injury Toby Alderweireld suffered during last weekend's 1-1 draw at West Brom.
Fans feared the Belgian defender was facing a significant spell out of the side after collidng with teammate Jan Vertonghen at the Hawthorns.
But Pochettino has given the 27-year-old the "all clear" after a scan revealed Alderweireld has avoided ligament damage.
