Neymar is out of the Paris St-Germain squad for their league match at Nantes on Tuesday with a rib injury.
The Brazilian, who needed treatment during PSG's victory against Montpellier on Saturday, celebrated his 28th birthday at a Parisian nightclub 24 hours later.
Manager Thomas Tuchel said his team selection would not be influenced by the timing of the party.
"Is it the best way to prepare for a match? No, clearly not," he said.
"Is it the worst thing in the world? No," the German added in his news conference on Monday.
"I always protect my players, and I really love my team. With this party, I accept that it is a bit difficult to protect the players, but the context is not simply black or white," he said.
"It is a shame, because we are giving people the chance to speak badly of us. We need to adapt to the situation, but I am not going to leave a player on the bench or at home because they went out and celebrated."
The club confirmed on Monday that tests had shown Neymar suffered the cartilage injury during the first half of Saturday's Ligue 1 match.
Neymar was not the only PSG player Tuchel was questioned about - after a touchline spat with Kylian Mbappe in the 5-0 weekend win.
"There is nothing personal between him and me. These things happen," Tuchel said about his 21-year-old striker who reacted angrily to being substituted midway through the second half.
"It was between a player who does not want to come off, and a coach who had his reasons for doing something, and who wanted to give a game to players who deserved it."