Lampard is grateful for the chance to give his team more playing time, as well as progressing in the cup competition.
"We're in the position that this game for me is of course about getting through to the next round, it always would be, but I have huge eyes on the fitness of the team because we're not fit now, which means our pressing game and the speed of our game, it will be very difficult to attain the levels that we want," he said.
"So I'll use this game primarily for the first-team squad to get there. With respect to Barnsley and respect for the competition, it's a huge night for us for the fitness of our team."
Lampard continued: "We're in a very difficult position. I don't want to compare us to all the other teams, but we had pretty much as short a break as you can have because of our Champions League game against Bayern Munich, which took us two weeks beyond the regular season, and then we came back and played when everyone else started, unlike a few other teams in the Premier League.
"We also made some new signings, we also had double figures of quarantines at the start of pre-season, so we're clearly in pre-season mode and that's why we mustn't get too judgmental. I'm not being too judgmental of the squad at this point because we are short on fitness for individuals in the team.
"On top of that I want to work on how we play, what we do, what we're about. We showed fantastic stuff for big periods last year and we want to move that step further. So every moment to work now is a moment to improve, that means on the training pitch and that means against Barnsley tomorrow night."