However, Benitez added that he was hoping Italian midfielder Alberto Aquilani would recover from a virus that kept him out of Saturday's 3-1 defeat at Fulham for the Group E match.
Liverpool have to win to realistically keep alive their hopes of reaching the knockout round after losing their last two matches in the competition to Fiorentina and Lyon.
Benitez told the club's website (www.liverpoolfc.tv): "Aquilani had a virus. He trained today but was a little weak. Hopefully, in two days time he will be better."
But Gerrard, who has a groin injury which may need surgery, is definitely out of a game that Liverpool cannot afford to lose after winning just one of their opening three group matches.
"Gerrard won't travel to Lyon," Benitez said. "He has no chance. He is improving but we have to wait. He has had an injection but we have to wait two or three days and see how he reacts."
Benitez confirmed that striker Fernando Torres, who is nursing an adductor muscle injury, was part of the squad travelling to France, explaining: "We have to take Fernando to Lyon because we don't have too many options."
The club confirmed on its website that midfielder Riera and defenders Kelly and Skrtel were also definite non-starters.
(Editing by Ken Ferris)