Enzo Maresca said he had no choice but to rotate his Chelsea squad when questioned on Friday over his team's damaging 3-1 defeat at Leeds in midweek.
The loss at Elland Road on Wednesday left the Blues in fourth place, nine points behind Premier League leaders Arsenal.
"We did many things bad," Chelsea boss Maresca said. "Probably we also paid the bill for playing one hour with 10 players against Arsenal."
The Italian, who has previously been criticised over his rotation policy, made five changes for the game at Leeds.
Wesley Fofana was not included in the squad and Moises Caicedo was suspended while Malo Gusto, captain Reece James and winger Pedro Neto were named as substitutes.
But Maresca said his hand was forced.
"Most of the rotation we do is because the other one they cannot play," he said. "So we have players in this moment not able to play every three days.
"And the reason why we have done most of the rotation in the past is for this reason.
"It's always the same thing – when you pick 11 players and you win it's fine. When you pick 11 players and you don't win, it's always the reason why.
"For sure, playing with 10 players for one hour (in Sunday's 1-1 draw against Arsenal) then going to Leeds is not the best situation for us."
-- NIGERIA ONLY --
Maresca was asked ahead of Chelsea's game at Bournemouth on Saturday whether his young side needed an injection of experience.
"We always talk about experience when we drop points but when we beat Barcelona and drew against Arsenal, no one was mentioning about experienced players," he said.
He added, "I know that we are always looking for experience but it was a bad game (at Leeds) for all of us."