The Liverpool boss has spoken to Torres since the striker limped out of Spain's win over France on Wednesday and has satisfied himself the injury is a hamstring problem that will need a week, at least, to recover from.
Straight after that game, Torres claimed he "had every intention of playing against Chelsea on Sunday".
But although Benitez will await the report from a scan on his star forward, he insists the 23-year-old will not be risked at Stamford Bridge.
He said: "We know it is a hamstring problem. I have spoken to Fernando, I know what the problem is. This injury is at least one week.
"You cannot play on after an injury like this, it is a big risk. He will not play at Chelsea."
Benitez said: "We will wait for the result of the scan, but I have no doubt he will miss the weekend. When you leave the field like he did so early, and he knew what had happened, it does not change how long he will be out.
"I will talk to the doctor and the player, but it is a big blow. He was scoring lots of goals and I will now have to think of a different partnership.
"We have three big games in 10 days in three different competitions and we have lost our top goalscorer.
"It is difficult to be calm about it, this was another international friendly in a busy period for clubs at this time of the season."
He added: "It is crazy enough they go away and have different training systems, diets, new ideas. And they get injured.
"We have got some confidence back with a 3-0 win over Sunderland and a very good second-half performance. But then a lot of players are away all over the world and we are left to train with just a few, it makes things very difficult.
"It is hard to see who to blame for Torres' injury. But the authorities are talking of changing the schedule and to pay money if you lose players.
"That is three important competitions, and if you lose someone like Torres, who was scoring lots of goals, it is a big, big loss."