Both players have spent time in the treatment room and the Reds have suffered as a result by fading from the race for a Champions League place.
West Ham travel to Anfield tonight knowing that Torres is out because of a knee injury and Zola offers a simple explanation for Liverpool's problems this season.
"Gerrard and Torres are massive players, when they are on the pitch it makes a big difference to Liverpool," he said.
"It's a pity they haven't been available for the whole season because of injuries and Liverpool's problems lie within that.
"When they are in good form they can be a really good team. They can stand with United and Chelsea.
"But Torres has had too many injuries and it's a big ask for them without him."