Liverpool manager Jurgen Klopp says he's concerned about a potentially serious knee injury to captain Jordan Henderson.
The Reds captain was forced off at half-time of Thursday's 1-1 draw at Borussia Dortmund in the first leg of their Europa League quarterfinal.
"It's a disappointment with Hendo, it's a knee injury - not too good, so that's bad news," Klopp told BT Sport.
Henderson was seen leaving the stadium on crutches, and his manager did not offer a good prognosis in his news conference.
"Jordan is really frustrating because each team in the world needs a little bit of luck but it looks like we don't have it," Klopp said.
"We need to wait for the scan and we hope for the best, but it doesn't look good.
"I don't want to speculate, what can I say until we have the scan, but it is not a small thing, I think, but we have to wait.
"That's what we can say. We have to wait for the result of the scan."
Joe Allen came on in the second half and could feature in Henderson's place for the rest of the season.
Any serious injury would also damage Henderson's chances to feature for England at the European Championship this summer, especially as Arsenal's Jack Wilshere returns to fitness.