LIVERPOOL, England -- Sadio Mane is in contention to play for Liverpool in Wednesday's Champions League encounter with Red Star Belgrade, but Jordan Henderson and Naby Keita have been ruled out with hamstring injuries.
Mane sat out Saturday's trip to Huddersfield Town after undergoing surgery on the fractured thumb he sustained while on international duty with Senegal.
Henderson, meanwhile, came off at half-time at Huddersfield after complaining about his hamstring, while Keita is still suffering from the issue he picked up when playing for Guinea.
"Sadio looked good in training the last two days. He trained completely normal, so if nothing happens he should be at least in contention," Klopp told a news conference on Tuesday. "I learned that word a second ago, actually. That's good.
"Naby will not be available, nor will Hendo. Naby is on a good way again, running outside and all that stuff, but we have to see, take it day by day. We cannot put any pressure on, but it should not be that long until he is fit.
"Hendo got a little hamstring injury in the [Huddersfield] game. Not too serious, but serious enough that he's not available tomorrow or at the weekend. Then from that day on, we will count the other days until he's available."
Klopp is also hoping to be able to count on Georginio Wijnaldum and James Milner, who both picked up knocks on the weekend.
Liverpool's encounter with the Serbian champions on Wednesday takes on greater importance following the defeat away at Napoli earlier this month.
Red Star themselves were beaten 6-1 by Paris Saint-Germain in their most recent Champions League fixture, although that game has been marred by allegations of match fixing.
"For Red Star the challenge is a little bit that they are that dominant in Serbia, winning 80, 90 percent of their games," Klopp said. "And the Champions League is then different, against the top teams in Europe. It makes it difficult.
"But I really think they did well. They defended well against Napoli, they did everything well. And against Paris, if they open the box of Pandora, then it's different. Then Neymar scores from 30 yards with a free kick, nobody can defend that.
"I know that they are able to defend and to create as well. They have different possibilities to line up, different strikers, tall, quick, good footballers, good headers, full-backs are really on their bikes, offensive-orientated with a clear structure. Serbian teams are always well organised and can be a bit more aggressive.
"We need to be ready for a really hard fight, for each square metre of space, with all we have. And for that we need our crowd. We learned last season that atmosphere can make the difference, and that's what we have to make sure again.
"It's a hard group, for all teams, and we have to make sure that we make the next step against a really good side.
"I saw the qualifier against Salzburg when they celebrated, and they fought back from 2-0. They had five or 10 fantastic minutes to change the whole game, and when I saw them celebrate I knew that they would fight for getting points or even winning at Anfield."
There will be no away fans in attendance at Anfield on Wednesday as Red Star serve the final game of their ban on selling tickets for away matches as a result of incidents during their playoff with FC Salzburg.
Liverpool have sold a portion of Red Star's unused allocation to their supporters aged between 17-21 in efforts to get more young fans inside Anfield.
"When I was a player I played in empty stadiums," Klopp said. "They were not banned, they were just not interested in the football.
"A stadium full of only one crowd, I never experienced. The support here in England is different. We don't sing against another crowd, it's more you follow the game and support your team.
"Of course, it's not nice for the people of Belgrade, but we have no influence on that. We would have had no problem if their fans had been here, we'd still have had a fantastic atmosphere."