Despite his omission, Gerrard thinks that Rooney is too important to leave at home.
"For me he has got to go, the talent that he is," he told Sky Sports News. "He is that good a player, I think you have to take the risk and take him.
"We will have to see who we come up against in the group games but we should progress from the group stages and then you need your best player out there with you to push on all the way to the final."
Gerrard scored the game's opener in his side's 1-1 draw with United at Anfield on Saturday.