Defensive midfielders Sven Bender and Sebastian Kehl are both injury doubts for Borussia Dortmund ahead of Saturday's Ruhr Valley derby against Bundesliga rivals Schalke 04.
The pair failed to come through unscathed from Dortmund's 3-0 last 16, second leg win over Shakhtar Donetsk on Tuesday, which put Borussia in the Champions League quarter-finals with a 5-2 aggregate victory.
Bender played the first half against the Ukrainain champions before a knock on the ankle following a challenge on Shakhtar's Fernandinho saw him come off.
His replacement Sebastian Kehl came on despite suffering from broken ribs and aggravated his condition meaning the pair are rated doubtful for Saturday's league clash in Gelsenkirchen with Dortmund second in the table, but 17 points behind leaders Bayern Munich.
"That's the biggest problem with being a coach, you can celebrate for four seconds and then you go into the dressing room and hear the news," quipped coach Jurgen Klopp as Dortmund reach the Champions League's last eight for the first time since 1998.
"We have to wait and see how things are with Sven.
"Sebastian Kehl played with broken ribs, he could hardly breath or sprint.
"We have to shuffle things around and use every second for regeneration."
Despite breaking his ribs in Saturday's Bundesliga win over Hanover 96, Kehl still managed to finish the Donetsk game having come on just after the half-time break.
"I broke the ribs on Saturday, but it wasn't planned that I'd play so long and come on so early," said the 33-year-old.
"But the injury to Sven was pretty bad and he had to come off.
"It was pretty tough, I was in real pain. I can't say much about the derby, I'm not moving too well at the moment."