Liverpool manager Jurgen Klopp has revealed that defender Virgil van Dijk faces “more than a month” on the sidelines with a hamstring problem.

The 19-time English champions are 16 points behind Arsenal, who is leading the Premier League, and seven points behind the top four teams.

The 31-year-old Dutch defender got hurt in Monday’s 3-1 loss to Brentford and is likely to miss Premier League games against Brighton, Chelsea, and Wolves.

He is in a race against time to be ready for the Merseyside derby on February 13 and the first leg of the Champions League quarterfinals at home against Real Madrid the week after that.

“It is a surprise for us and obviously a big blow,” Klopp said on the eve of his team’s FA Cup third-round tie against Wolves.

“The diagnosis was pretty harsh and we talk about weeks, more than a month, but I hope it goes quick. He never had an issue with muscles before and it just now happened. It was one sprint too much in that moment.”

Cody Gakpo, who move from PSV Eindhoven to Liverpool was finalised this week after he did well at the World Cup, could make his debut for Liverpool on Saturday.

“I’m very positive about him,” said Klopp. “Cody gets the same amount of time like each player. You have to settle in offensively, it’s not that easy. He comes in from a different league. That’s always difficult.”

He added: “Of course with our situation, injuries to the strikers as well, it’s really nice to have a player who is pretty natural in a lot of things in the offensive part of the game and knows where the goal stands.

“He is obviously full of joy, enjoying each second in the moment. That is very good. He looks really good, really promising.”