Liverpool assistant manager Pep Lijnders confirmed the news ahead of the club's Carabao Cup semi-final first leg against Fulham on Wednesday, live on Sky Sports.

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Alexander-Arnold, who has been pivotal for Liverpool this season in a hybrid right-back and midfield role, is set to be sidelined for around three weeks, which rules him out of both semi-final legs against Fulham, a league trip to Bournemouth, and the club's FA Cup fourth round tie against Norwich or Bristol Rovers.

The defender may also be a doubt for Liverpool's home clash against Chelsea on January 31, as well as a crucial title race trip to Arsenal on February 4.

"Trent hyperextended his knee during the last game [against Arsenal in the FA Cup third round]," says Ljinders.

"So he has a little tear in the lateral ligament of his knee and he will need time to recover. He had a scan and he will be out for a few weeks, so let's see after that.

"He will get some rest and then hopefully he can come back to where he was. Because this guy was decisive in all the games and was the one who created constantly for us from deep and gave the team a high level of flexibility.

"We will really miss him."

With Alexander-Arnold out, it could see a run in the Liverpool team for Northern Ireland defender Conor Bradley. The 20-year-old played the final few minutes of Sunday's 2-0 win over Arsenal in the right-back role.

"We have many weapons so there is no-one irreplaceable here," added Liverpool assitant Lijnders. "Mo [Salah] goes away, [Diogo] Jota steps up.

"We don't rely on one, two, three or four players. We are missing four or five core players from our leadership group - Robb, Trent, Mo - so that's a blow of course and he creates a lot of flexibility from the back and he can play passes that the forwards really like.

"He has physicality, he knows how to decide games and knows where to put balls but the squad has a lot of other qualities in my opinion. But for sure we need to find new dynamics."

Liverpool's next six games - can Trent get back in time for Arsenal?

January 10: Fulham (H) - Carabao Cup semi-final first leg, live on Sky Sports, kick-off 8pm

January 21: Bournemouth (A) - Premier League, live on Sky Sports, kick-off 4.30pm

January 24: Fulham (A) - Carabao Cup semi-final second leg, live on Sky Sports, kick-off 8pm

January 27: Norwich or Bristol Rovers (H) - FA Cup fourth round, date/time TBC

January 31: Chelsea (H) - Premier League, kick-off 8.15pm

February 4: Arsenal (A) - Premier League, live on Sky Sports, kick-off 4.30pm

Van Dijk back for Liverpool, left-backs to return by February

There was more positive news for Liverpool's defence in terms of injury news, with Virgil van Dijk due to return after he missed Sunday's FA Cup win over Arsenal due to illness.

Meanwhile, Dominik Szoboszlai is back in light training after picking up a hamstring problem, but will not be fit for Wednesday's Carabao Cup last four clash with Fulham.

Left-backs Andy Robertson and Kostas Tsimikas, who picked up shoulder and collarbone injuries respectively in recent weeks, are due back by the end of January.

"Virgil is back," said Lijnders. "He did some runs yesterday on the pitch, looked good again. So he will be back in the squad [on Wednesday], he recovered well. So it really helped him not to travel to London.

"Dom is progressing well on the pitch, he's running, so let's see. Not available for tomorrow.

"And then we have Robbo, he's almost at the three-month mark, so he will get checked by the surgeon.

"And if he does that scan and we see everything [so] that we can really progress him, he will go to Dubai for a week to do proper volume sessions, proper sessions, so that will be good for him. Then we see the three-month-mark scan and then we can see how quick he can go into contact again.

"Same for Kostas. Kostas is progressing really well, really quick. So hopefully both of them - Robbo and Kostas - will be back at the end of this month to train with the team."

Analysis: Is Trent injury a title race twist?

Sky Sports' Sam Blitz:

"With Mohamed Salah out for up to a month due to Egypt's Africa Cup of Nations campaign, Liverpool's right-hand side - such a big weapon for them down the years - has been depleted.

"Alexander-Arnold is, alongside Salah, Liverpool's most creative player. Only Salah has created more big chances in the Premier League this season than Alexander-Arnold, underlining the idea that Liverpool fans are not the only ones who will miss the England defender in the coming weeks.

"One statistic that stands out when it comes to Alexander-Arnold is how he tops the charts for switches of play this season. He makes Liverpool's play more unpredictable and the likes of Darwin Nunez, Luis Diaz and Diogo Jota will have a lower level of service in the coming games.

"Liverpool will be happy that a 10-day winter break this month softens the blow of Alexander-Arnold's injury ever so slightly.

"But Jurgen Klopp will be keen to get his key creative influence at his peak fixtures at the end of the month for back-to-back fixtures against Chelsea and Arsenal.

"Liverpool drew the first round of fixtures against both those London teams this season. With Manchester City back on the up, they cannot afford too many slip-ups between now and May. Time will tell if this injury blow for Alexander-Arnold is a title twist."