Liverpool's season has suffered another blow with the news that Charlie Adam will miss the rest of the season with lateral knee ligament damage.

The Scottish midfielder suffered the injury in the 3-2 defeat at Queens Park Rangers on 21 March and will not play again before next season. The 26-year-old has had a disappointing first season at Anfield after his breakthrough at Blackpool last term. He has played 35 times for Liverpool but scored only two goals, against Bolton Wanderers and West Bromwich Albion, the second of the two coming on 29 October 29.

Liverpool have been without the central midfielder Lucas Leiva since November but the manager, Kenny Dalglish, still has several options in that position, including Steven Gerrard, Jay Spearing, Jordan Henderson, Dirk Kuyt and Jonjo Shelvey, as he tries to improve the team's fortunes.

Liverpool have won one of their past six Premier League matches and are now 13 points off a Champions League place. The defender José Enrique said on Tuesday that the players, not Dalglish, were to blame for the team's form.

The manager has defended his team almost without question – the 3-1 defeat at Bolton Wanderers in January the notable exception – and that has led to more criticism coming his way. However, José Enrique said Dalglish was taking the flak on the players' behalf and that the squad need to look at their own performances and address the situation.

"The manager takes pressure for us and of course that is good," said the Spaniard. "But the truth is, when we make mistakes or have a bad game, we know where the mistakes come from. Who plays the games? The players. Who has to win them? The players too.

"The players are frustrated just the same [as the fans]. We have played good football in many games but against Wigan we didn't deserve to win."

José Enrique was one of seven signings brought in by Dalglish in the summer and was the most consistent of those arrivals until recently, when even his performances have looked shaky. "I am really grateful to him," said the 26-year-old.

"Of course I want to do my best for the team and for Liverpool first but also for the manager because he signed me. In the cups we are doing well. Liverpool went many years without winning something and already we have one cup and we are playing for another one," he told liverpoolfc.tv.

"In the league I think we deserve more than where we are now but the truth is we are in seventh position. This team is in production; the owners have signed young players. I think we have a really good squad already but of course we have to improve – everyone."