Torres has been plagued by hamstring problems over the past 18 months, suffering the injury five times in that period.
Liverpool are currently analysing his training schedule with both club and country in an attempt to resolve the problem.
Benitez had questioned the Spain training regime and believes it could be the cause of his injury.
"He has been injured now three times while with the national team and it is something we have to analyse," he stated.
"We knew they were doing something that is maybe not the best for the player."
It had been hoped he would return by mid December but Torres will now miss Premier League games against Blackburn, Hull, Arsenal and Bolton and Tuesday's Champions League tie against PSV Eindhoven.
He could return for the trip to Newcastle on 28 December.
Liverpool have struggled in recent weeks in the absence of last season's top scorer, with new signing Robbie Keane still finding his form since his £20m move from Tottenham in the summer.
The Reds currently top the Premier League but have drawn their last two home games without scoring a goal.
Torres himself is committed to returning to the side to boost their title credentials.
He said: "The only thing to do is to get on with the rehabilitation and make sure that I come back when I am ready and not too soon."
Portsmouth TodayNew hamstring woe for Torres Liverpool striker Fernando Torres will be out of action for two to three weeks with a hamstring strain picked up in the Champions League win over Marseille. - 36 mins ago
Dominion PostLiverpool's Torres sidelined again - 1 hr ago
ReutersLiverpool lose top striker for up to three weeks - 1 hr ago
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