The £20 million midfielder has barely played since joining the club injured from AS Roma in the summer - with Saturday's game against Wolverhampton Wanderers being the first Premier League match he has started.
But Aquilani came off in that game with a hamstring injury to raise further questions about his overall fitness after years of niggling problems.
Benitez refuses to bow to pressure to play the Italy international more regularly as he tries to find answers to the club's poor form in the first half of the campaign.
Benitez said: "Aquilani did well against Wolves, but he needs match fitness. He was trying to be involved, passing and creating chances, but the Premier League is difficult and he will settle down little by little.
"It is a difficult decision with the Villa game coming so quickly. Some of our players were very tired after the Wolves match, while some had little injuries. We will need to assess them all.
"We will have to manage them carefully but clearly if Javier Mascherano is not available for the next three games through suspension, then Aquilani will obviously have more chance of time on the pitch.
"But against Wolves he was worried about his hamstring, he was concerned and I wanted to protect him. That is why we took him off.''
Benitez could play Steven Gerrard in a deeper role. The Spaniard said: "Maybe we would normally have two holding players for such a game, but we have options. Gerrard can play in that role, we will see.
"Lucas was tiring against Wolves, he was not well, but now we must see how he recovers and whether he can have more energy now. It all depends on how the players feel and react after the Wolves game.''