Liverpool striker Fernando Torres will not feature when West Ham travel to Anfield on Monday.
The Spain international missed last weekend's goalless draw against Fulham after flying to Barcelona to have a knee injury assessed by a specialist.
Having returned to Merseyside for the Hillsborough memorial service he was due to fly out to Spain for another examination by the surgeon who operated on the knee in January but the closure of British airspace for the volcanic ash cloud has delayed that.
Benitez would not consider playing Torres until a second examination took place, and that brought bad news with the Spaniard now set for a six week layoff that puts his World Cup participation in doubt.
Defenders Emiliano Insua and Fabio Aurelio are both still out so Daniel Agger is set to continue at left-back.
With four games remaining Liverpool can only reach a maximum of 68 points, which means they are relying on their rivals having a dreadful run-in.
But while it is still mathematically possible to secure Champions League football next season Benitez will keep believing.
With a Europa League semi-final against Atletico Madrid also to contest the Reds boss is confident they can still have a successful finale.
But he does not feel under any additional pressure to deliver just because co-owners Tom Hicks and George Gillett officially put the club up for sale on Friday.
"Everyone knows Liverpool are a top side and one bad season is not going to be changed by winning one or two games at the end," he said.
"Clearly the Europa League will bring some silverware but in terms of the value of the club it is massive so we don't need to think about one or two games.
"Always in football things can change in one week but we have to win our games.
"For us it is not difficult to concentrate on our job, it is just to win four games, get 12 points and see what happens.
"I think we deserved to win against Fulham but we couldn't so we have to make sure we do it against West Ham and in the other games."
West Ham midfielder Scott Parker is suspended as he completes his two-match ban.
Luis Boa Morte is close to full fitness after recovering from a knee injury but will not be risked at Anfield despite having played for the reserves.
Kieron Dyer (hamstring), Herita Ilunga (knee), Jack Collison (knee) and James Tomkins (ankle) are out but Mido is back after missing the 1-0 victory over Sunderland through illness.
The limelight at Upton Park has shifted away from Carlton Cole and onto Ilan, the January arrival from St Etienne who has scored twice in the last two games.
The goals, lifting the Brazilian's tally to three in seven appearances, have helped West Ham collect four precious points in their battle against relegation.
"Ilan looks bright. The thing I like about him is his freshness and presence. He is lively," said Zola.
"He has an eye for goal and always in good positions for goals.
"Even in the first game he played, he scored once and looked dangerous from every occasion.
"To start with he wasn't adapting to the game quickly, that's why he wasn't playing.
"Now he has found his way in and he's doing very well, scoring important goals for us."
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