Benitez is already without Glen Johnson because of a knee injury sustained in the win at Aston Villa on Tuesday, while midfielder Javier Mascherano is still serving a suspension.
Liverpool need to do well in the FA Cup considering their poor season, so Benitez will mix his side with experienced and fringe players. Winger Albert Riera, back in training after a calf injury, is unlikely to be involved.
Reading have no fresh injury concerns but caretaker boss Brian McDermott may choose to make changes after the 4-1 defeat at Plymouth on Monday.
Defender Matthew Mills is expected to be handed a recall as McDermott looks for a response to a damaging defeat at Home Park which left the Royals just two points clear of the Championship relegation zone.
Midfielder Brian Howard has been an unused substitute for the last two games after a swift return from a broken jaw and may be back in the starting line-up and be given a chance to emulate his famous FA Cup goal at Anfield while a Barnsley player in 2008.
Jay Tabb is still struggling with a calf strain while striker Noel Hunt is likely to be out until the end of the season as he recovers from a knee injury.
New signing Gunnar Thorvaldsson is not available to play until next week's clash with Newcastle.
Liverpool (from): Reina, Carragher, Agger, Skrtel, Aurelio, Insua, Darby, Dossena, Benayoun, Gerrard, Kuyt, Babel, Kyrgiakos, Spearing, Aquilani, Lucas, Ngog, Pacheco, Cavalieri.