It was expected that the Spaniard would be be back in action after a fortnight but Liverpool boss boss Rafael Benitez admits he could be out for a good deal longer.
Torres has suggered six hamstring injuries in the past two years.
Benitez said: “We said two to three weeks at first but do not want to put a time on it now.
“We want to resolve this problem once and for all and will not rush him.”
Torres said: “The only thing to do now is to get on with the rehabilitation and make sure I come back when I am ready and not too soon.”