Jurgen Klopp has revealed that injury-ravaged Liverpool forward Daniel Sturridge has suffered yet another setback in his bid to return to full fitness.

The England international has made just six first-team appearances for the club this season and none since playing as a second-half substitute during the 2-0 defeat against Newcastle United at St James’ Park on 6 December.

Although a hamstring injury has been the latest problem to afflict Sturridge, the 26-year-old has also been forced onto the sidelines with foot, knee, hip, groin and thigh injuries since almost Liverpool to the Premier League title in the 2013-14 season.

And with Klopp insisting he would only restore Sturridge to his squad when fully fit, the Liverpool manager has now admitted that the former Manchester City and Chelsea forward has been unable to keep pace with his pre-assigned rehabilitation programme.

"Daniel had some problems, not serious, but he could not make a session and we had to wait a day,” Klopp said. "Because he didn't have one session with the team it was not the usual plan for this week.

"It would be easy for me to say 'Come on, let's try, we have problems, we don't score enough goals, let's see what will happen' but we have to wait and be patient.

"It is how a pre-season can be. Some little things happen and we have to handle this. It is not a row of sessions and we say 'Now we are here and go...”

West Ham 2 Liverpool 0 player ratings Show all 22 1 /22 West Ham 2 Liverpool 0 player ratings West Ham 2 Liverpool 0 player ratings West Ham: Adrian 6 out of 10 Pulled off a number of important saves to keep Liverpool at bay but wasn't overly challenged. 2015 Getty Images West Ham 2 Liverpool 0 player ratings Tomkins 6 out of 10 Wasn't able to get forward as much as Cresswell but solid at the back. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Collins 8 out of 10 Man of the match performance and led from the back. At the heart of West Ham's defence, keeping Benteke quiet all game. 2015 Getty Images West Ham 2 Liverpool 0 player ratings Ogbonna 6 out of 10 Relatively quiet game but did a job at the back and was especially strong at dealing with Liverpool's set pieces. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Cresswell 7 out of 10 Fulfilled his defensive duties well but also proved a menace going forward down the flank. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Antonio 8 out of 10 Industrious performance from him. Kept Liverpool's defence busy all game with his runs and scored West Ham's first goal with a great header. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Kouyate 6 out of 10 Did a decent job in the middle but wasn't able to keep the Liverpool midfield completely quiet. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Noble 7 out of 10 A tireless performance from the captain. Never stopped running and did particularly well in breaking up play. West Ham 2 Liverpool 0 player ratings Lanzini 4 out of 10 An early injury meant he couldn't really get going. Was brought off before half time. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Carroll 7 out of 10 Took his goal well and was certainly more threatening in the second half. As expected, used his height to his advantage and was a danger in the air. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Valencia 7 out of 10 Like Antonio, used his speed to threaten the Liverpool defence and created a number of chances for the home side. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Liverpool: Mignolet 6 out of 10 Did well to keep the score line what it was but still conceded two goals. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Clyne 6 out of 10 Got well forward, especially in the first half, but wasn't able to prevent West Ham balls into the box. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Lovren 5 out of 10 Uninspiring game from him. Couldn't deal with West Ham's threat up front and was caught out on a number of occasions. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Sakho 5 out of 10 Another disappointing game from him in which he added very little. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Moreno 6 out of 10 Made a number of important tackles and worked hard, but couldn't save his team. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Can 6 out of 10 Enjoyed one of Liverpool's best chances on goal but it was a quiet game asides from that. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Lucas 5 out of 10 Failed to make his mark on the game. Looked overwhelmed in the middle. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Ibe 7 out of 10 Liverpool's most threatening player down the right and created a number of chances. 2016 Getty Images West Ham 2 Liverpool 0 player ratings Firmino 6 out of 10 Mixed performance. Guilty of some sloppy passes and defending but looked lively going forward at times. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Coutinho 6 out of 10 Was far more dangerous in the second half but could only resort to ambitious shots from outside of the box. 2016 Liverpool FC West Ham 2 Liverpool 0 player ratings Benteke 4 out of 10 Offered Liverpool very little up front. Far too static and a heavy touch let him down throughout the match. 2016 Getty Images

With Sturridge unable to complete a full pre-season campaign with Liverpool since arriving at Anfield in January 2013, Klopp insists that the player must now go through a ‘mid-season pre-season’ before returning to first-team contention.

“I will pick him when he is ready, I will not hold him back,” Klopp said. “But what Daniel has to do at this moment is hard work to be prepared for the things we make in a football game.

“He had the last complete pre-season in 2011 or 2013 - it is a long time.