Liverpool manager Juergen Klopp said centre back Virgil van Dijk had made good progress in training as the Dutch international prepares to return from a serious knee injury. Van Dijk, 30, has been sidelined since undergoing surgery on a knee injury he picked up in the Premier League match against Everton in October. Van Dijk, Joe Gomez (knee), Joel Matip (ankle) and Trent Alexander-Arnold (thigh) are all working on their fitness and took part in Liverpool's pre-season training in Salzburg, Austria. "All four look really good, I have to say," Klopp told the club website. Virg and Joe will not have double sessions now for the first few days with the team ... I don't know exactly when we can make the next steps but it will happen in the next four weeks, for sure – we will get a big step forward. "Joel looks good, absolutely, he is the closest probably to normal training. Trent was a serious enough injury but now not a major one, I would say. He is close but in the moment, probably the next five or six days he has a special programme." Liverpool, who finished third last season, begin their new league campaign at promoted Norwich City on August 14. <br/>