Brendan Rodgers has said he is no longer concerned by Liverpool's ability to handle direct, physical opponents, as he prepares for Sunday's reunion with Andy Carroll at West Ham United.

The Liverpool manager has admitted in the past that his defenders have been bullied by powerful centre-forwards or lapsed at aerial challenges. The former £35m Liverpool striker Carroll will pose that threat when the league leaders take their title challenge to Upton Park but Rodgers insists there has been a vast improvement in that aspect of his side's game.

"It's one where hopefully, as time has gone on, they understand the concepts that I want," said Rodgers, who is hopeful Daniel Agger will be available despite suffering a slight foot injury in training. "I don't want rash defenders. I want defenders to work with intelligence.

"You've seen Martin Skrtel's form. He very rarely goes to ground now. He very rarely gives away free-kicks. His intelligence as a defender is first class. His aggression to go and attack it at the right time has been first class. Daniel Agger is a No2 centre-half who can go and head it and cover. And when he's not available for whatever reason we have Mamadou Sakho, who is aggressive, strong and can really dictate to the opponent. It's all part of the learning and hopefully we've learned. We've come up against big centre-forwards and dealt with it well."

Rodgers insists it is "consistency in our concentration" that Liverpool have lacked in defence at times this season rather than quality or an ability to deal with set pieces. One of his first tasks as Liverpool manager was to inform Carroll, the club's record signing, that he did not feature in his plans. He may, however, make special arrangements for the West Ham forward on Sunday.

"There's no doubt that West Ham's strength is to be direct, get it up, in and around the box, have runners into the box and from corners," he added. "And you saw big Andy the other night score a good header from a corner [against Sunderland] but that is what we have to cope with. We've done it before and I'm sure we can do it again.

"It's very difficult to stop a goal like that. I think it's one of the great sights in football when you see a big target man really go and attack the ball with aggression but you can cope with it. We have had it with Christian Benteke. Last year I put two men on him, Jordan Henderson and Jamie Carragher, and you create a cage around him. That restricts the mobility. You can't let someone of that ilk, whose strength is attacking the ball in the area, have a free run at it."

Iago Aspas has admitted he will seek a permanent transfer from Anfield this summer, having made only 13 league appearances since a £7.2m arrival from Celta Vigo. The 26-year-old striker, whose chances have been limited by the outstanding form of Luis Suárez and Daniel Sturridge, has said: "I'm not 20 years old any more, I can't go on loan and explode. I think the best would be to transfer to another club where I can find the best fit for myself and the club."