The Foxes lost 4-2 to Chelsea after extra-time in the third round of the EFL Cup having started with the likes of Shinji Okazaki (who scored a first-half double), summer signing Ahmed Musa, wingers Demarai Gray and Jeffrey Schlupp and defenders Marcin Wasilewski and Ben Chilwell.
Of the defeat, which gave opportunities to some players in need of minutes, Ranieri said: "Shinji was very determined.
"It is good because between Shinji and (second-half sub Leonardo) Ulloa they want to fight to have a chance.
"For us that is good.
"And also I watched Jeffrey Schlupp come back after his injury, Ben Chilwell, Demarai Gray and Ahmed Musa must understand much better the Premier League, but it is okay.
"For me it is important to develop all the squad and not just the 14 players.
"We have a chance to go through to the next round but it wasn't possible, but it is okay.
"Of course now we have to work more and more to give them 90 minutes because when I need them they must be fit 100 percent."