The Blues’ boss also says Kyle Walker will be checked over after appearing to be in discomfort as he left the pitch.
Pep also gave an update on David Silva and Kevin De Bruyne’s determination to play just 48 hours after being stretchered off at Selhurst Park.
“Gabriel will be out for between four to six weeks, or a little bit longer, but hopefully as soon as possible,” said Pep.
“As for Kevin, he told me he wanted to play tonight. He was in pain because it was a kick he received, but if he wants to play, I want him to play.
“Nothing will change my opinion about his quality, everyone knows about his quality. Kevin wanted to play. Everyone will try to follow his desire.
“We are very happy David Silva is back with us. We don’t know how long he will be with us, but you saw again today he essential player for us.
“David is free to stay or to leave whenever he needs to. It depends.
“He wants to stay and help us and because he loves to play for City, but family is the most important thing in life. I would never push him. If we drop points because he is not with us, so be it - family is everything and must come first.”
When questioned about Walker and whether he had picked up a knock, the boss gave a brief update, but also said the festive schedule is too much for players.
“We are going to check Kyle out,” he said. “What I’ve seen in the last weeks is how many injuries the players have. We are going to kill them. The federation needs to reflect.
“I know the show must go on, but this is not normal. They control us - but we don’t protect the players. The people come here to watch the players and enjoy their performances - not the managers in the press conferences or the journalists who write about the game.
“In England, you don’t protect the players. You can’t play every two days. You don’t have to change the festive fixtures, the Boxing Day games and so on, but you can’t play the morning in Selhurst Park, come back, celebrate New Year’s Eve, and then play two days later.
“The show must go on and we try - the physios, doctors, nutritionist - to protect them. The tradition is the tradition, but we have to think about it a little bit. The players are artists and they are the reason we are here.”
On the Blues’ 3-1 win over Watford, Pep said he was delighted by his team’s reaction to Sunday’s draw with Palace, adding: “It was the first time we dropped points in 18 games and you saw the reaction.
“Except for 15 mins in first half when we were not good enough, we lost simple balls and they created two or three chances.
“In the second half, when we could have been tired, it was completely the opposite. We could have scored more, but I am happy.”