"It's a shame for the team, the club and especially for the player because he is a very important member of the squad," Rijkaard told a news conference on Friday.

"But our aim is to keep working hard so that when he comes back he will be rejoining a side that is in strong shape. I think we have the players that will enable us to continue to make good progress."

Eto'o, who has scored 68 goals for Barca since signing from Real Mallorca in 2004, will be out for up to five months after undergoing surgery to repair a torn meniscus in his right knee suffered during Wednesday's 1-1 draw against Werder Bremen.

He will miss the remainder of Barcelona's Champions League group games, the FIFA Club World Cup and up to 20 league matches.

Although the Cameroon striker has been the club's leading scorer for the past two seasons, Rijkaard still has an embarrassment of riches at his disposal in attack.