Liverpool manager Jurgen Klopp has admitted that Virgil van Dijk will be out for "more than a month" with the hamstring injury that he picked up against Brentford on Monday.

The Dutch centre-back was withdrawn at half time at the Gtech Community Stadium in that 3-1 defeat, in what was originally thought to have been just a precaution.

However, reports have since stated that Van Dijk's hamstring issue is worse than first feared, and he could miss the rest of the month while he recovers.

Liverpool will begin the defence of their FA Cup at home to Wolverhampton Wanderers on Saturday night, and Klopp addressed the media in his pre-game press conference on Friday.

When asked about Van Dijk's condition, Klopp confirmed that the 32-year-old would be sidelined for a number of weeks and admitted that the diagnosis was "pretty harsh".

"Virg is a big blow for us - he didn't feel it a lot. I took him off actually - in the end the diagnosis was pretty harsh," Klopp told reporters.

"We're talking about weeks, more than a month. Hopefully it goes quick, we will have to see. We cannot use him on the pitch but we will use him off the pitch."

Elaborating on Van Dijk's injury to the official Liverpool website, Klopp added: "It's not a short-term and I had longer-term injuries as well in my career as a manager. So, it's somewhere in between. He will be out for a few weeks, definitely."

Van Dijk had not missed a single minute of football in any competition for Liverpool this season before coming off at half time against Brentford, and he joins a lengthy list of players on the sidelines.

Luis Diaz, Arthur and Diogo Jota remain absent with their long-term issues, and it remains to be seen if James Milner and Roberto Firmino can recover from their hamstring and calf issues in time for Saturday.

However, Jordan Henderson - who missed the defeat to Brentford due to a concussion - has been taking part in full training and should be in contention for the FA Cup tie.

"He did exactly what he was allowed to do yesterday – big parts of team training without heading. And from today on, I think he's completely allowed to do everything," Klopp said of the England midfielder.

Despite the hectic schedule and wealth of injuries, Klopp has insisted that he will still put out an XI capable of winning the contest, saying: "We played on Monday, now Saturday. We will line up as strong as we can. We always did, but with Monday/Saturday, there will not be a rotation because of different competitions."

Nat Phillips, Joe Gomez, Joel Matip and Ibrahima Konate represent Liverpool's centre-back options with Van Dijk out injured, although the former has been linked with an exit amid his lack of game time.

With Van Dijk not expected to be back until the end of the January transfer window, though, Phillips is unlikely to depart Anfield during the current market.