Rafael Benitez believes the injury absence of centre-back Daniel Agger cost Liverpool in the race for the Premier League title last season.The Danish centre-back proved to be one of Liverpool's most consistent performers in 2006/07 as Liverpool reached the Champions League final.

Agger, though, missed the majority of last season with a recurring foot problem after breaking a metatarsal in the first half of the campaign to leave veteran Sami Hyypia and Jamie Carragher forced to play a combined total of 62 league games.

And, as a fully-fit Agger returned to pre-season training on Thursday, Benitez admits the 23-year-old has been missed at Anfield as youngster Jack Hobbs and full-back Alvaro Arbeloa were also forced into central defensive duty.

"I think it cost us early in the season," Benitez told Liverpool's official website.

"We conceded goals at the end of games which finished as draws because Sami Hyypia and Jamie Carragher were playing too many games in a row.

"We were using Jack Hobbs in some games and Alvaro Arbeloa as a centre-back; clearly we missed Daniel Agger.

"He is a centre-back but good on the ball and a threat for the other team too. We missed Agger."

However, Benitez has praised the contribution of Martin Skrtel, who arrived as a £6million signing from Zenit St Petersburg in January.

Benitez added: "We knew this player when he was 18. It was funny because some people were going to see Everton against Zenit and were saying this player really has ability.

"But we already had four or five videos of him which we liked. We had already sent our people over there and we knew he was the player for us.

"It can be difficult to settle down in this country but Martin has been really good."

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