Thomas Tuchel revealed his concern for in-form striker Mauro Icardi, who had to be substituted in the second half of Paris Saint-Germain's 1-0 win over Club Brugge.
Icardi scored the only goal as PSG booked their place in the Champions League's last 16, although they were also grateful to goalkeeper Keylor Navas for a late penalty save.
But on-loan striker Icardi was dealing with an issue as he made way for Edinson Cavani, Tuchel announced after the match.
The Inter man did not appear to be in any obvious discomfort but has been playing with pain for some time, according to his coach.
"It was the plan to change it after 65, 70 minutes. Then Mauro was injured and it was absolutely necessary [to bring on Cavani]," Tuchel told RMC Sport.
"[Icardi is] having treatment now. I'm always worried – we have too many injuries. He was in a lot of pain, but he is used to playing with pain – as he did like that against Real Madrid and Galatasaray.
"I think he's still strong, and that's not too bad."
PSG have dealt with injuries to Cavani and Kylian Mbappe this season, while Neymar remains sidelined. But Icardi has scored eight goals in his first nine matches for the club.
Although the Ligue 1 champions advanced on Wednesday, their overall performance was underwhelming as Brugge could easily have claimed a point – in complete contrast to a 5-0 domination in Belgium.
Tuchel was not too concerned, though, adding: "I'm happy. I knew it would be tough against Brugge.
"They play a very special style with a lot of possession – they are used to having the ball. You had to be focused and not lose possession often. I am very happy.
"[Brugge] have played about 25 games this season and lost twice – against us. Across two games, we won 6-0. It's good."