Benitez has praised his £7m signing and says Crouch is an integral part of the team he is building at Anfield.
"Sometimes you want to protect the player and we have enough good strikers to change, so when a player is working really hard and we have options on the bench, then we can change things," he said.
The last few games in which Crouch has come off, we knew he was playing well but we wanted to give confidence to some of the other strikers and support them.
"If you want to press high up the pitch like we do, then the strikers need to work really hard as well. Crouch is working really hard for the team and sometimes you need fresh legs.
"We have Crouch, Morientes, Cisse and Fowler, so we have the players to change things around.
"Crouch is running a lot, and as a striker it is not easy to do that. I had one player at Extremadura called Igor Gluscevic who ran more than any other player and ended up scoring 24 goals one season. Crouch is working a similar amount.
"But the most important thing is that he is doing more than simply running about. He gives us other options in attack. He is improving, but perhaps he can say better than me in what areas he is doing better.
"He is doing the same things now as he was earlier in the season, but he now has more confidence and more game intelligence."