Lampard has scored 12 goals in all competitions so far this season and he is now three goals short of Bobby Tambling's all-time record of 202 goals for Chelsea.
The England midfielder has been an integral part of the Chelsea team this season but Benitez has chosen to leave him out of the last-32 second leg clash, with the hope of keeping him fresh for Sunday's trip to Manchester City.
Lampard scored his 199th goal for the Premier League club in the FA Cup victory over Brentford on Sunday and looks certain to pass Tambling's mark before the end of the season.
"Lampard will not be in the squad tomorrow because we have to manage it a little bit," Benitez said at his press conference on Wednesday.
"If he can score goals it will be fantastic for him and will be fantastic for us.
"Everybody knows that he is close. I am sure they will try to help if they have a chance. If we have a penalty, he can take it and things like this.
"But the main thing is he's doing well, scoring goals. We have more competition now and that's good for me. It's a problem but a good one because we have too many games, so to have many players available is good."
Benitez also drew comparisons between Lampard and Steven Gerrard, who the Spaniard managed during his time at Liverpool.
"In terms of liking to score goals and their timing getting into the box is really good, that's their similarity," he added.
"Both are offensive midfielders who can score every game. They can take penalties, free-kicks and can still score in open play. They are two great players.
"It's important to have these kind of players, they are good professionals, who train properly and stay fit. He's doing that so I have to manage him."