The Reds skipper was forced off during the UEFA Champions League win in France and scans have now revealed a hairline fracture.
Gerrard will play with the injury against Chelsea on Sunday, but he will then be required to rest for at least seven days - which rules him out of England's friendly with Germany.
Rest needed
"We have been told by our doctors that this is not a big risk but he will clearly then need to rest after the Chelsea match," said Benitez.
"He will need one or two weeks' rest.
"He will train but he will not be able to join up with England.
"I will talk to Steve McClaren and I am sure he will understand."
------------------------------------------------
From LFCTV
Steven Gerrard will be available for Sunday's showdown against Chelsea despite suffering a hairline fracture in his toe.
Scans this morning revealed the midfielder sustained a minor fracture during Wednesday's Champions League qualifier in Toulouse.
Rafa Benitez said: "He has a hairline fracture in his toe. I think he will be available for the weekend. The only problem is, if we push him now, he might need a little bit of a rest afterwards.
"I was talking to the doctor and he said it is not a big risk for him to play, though there is always some risk."
Benitez revealed Gerrard may need one or two weeks of rest if selected against Chelsea, which in all likelihood will rule him out of England's friendly versus Germany on August 22.
"If we want to push him for this game, it would be a risk to push him again and again, because it could become more serious," said the Spaniard.
"I still need to talk to Steve McLaren but I think he will understand it would be a big risk."
