Kelleher recognises Plymouth's players will be up for the clash.
“I think obviously it’s going to be difficult,” he told liverpoolfc.com. “It’s obviously a massive game for them, us coming there is going to be huge. They’re going to be ready.
“The fans are going to be ready for us. It’s going to be a tough game. We want to go there and get a win, and we need to be ready for a tough game as well.
“Maybe they’re not having the best season but that kind of goes out of the window in a cup tie. They might see it as a chance to ignite their season and get something going, especially with us coming into town.
“It’s going to be a massive day for them. We know they’ll be well up for it.”
On the likely rotations for today's team selection, Kelleher continued: “I think definitely the manager alludes to that a lot in his meetings with us.
“It’s a squad that everyone needs to be ready to step in and everyone needs to play their part.
“He shows us all the time that there’s times in the season when you have injuries and in certain situations like that, squad players need to come in and do their bit as well.
“We train how we play, we’re always on it every day. That breeds good intensity into the squad, and everyone is ready to step up if needed.”