Chelsea received three red cards in three games.
The 22-year-old received the first red card of his professional career against Leicester City on Saturday.
The Blues won 2-1 over the Foxes thanks to a brace from new signing Raheem Sterling.
Conor Gallagher took to Instagram to apologise to everyone at Chelsea after getting sent off against Leicester.
Gallagher said: “Proud of the team for digging deep today and winning with 10 men.
“Personally, I want to apologise to my teammates, staff and the fans. I take full responsibility for the rash decision leaving them with a huge challenge for the rest of the game. Thankfully they came through.”
Manager Thomas Tuchel gave his verdict on the red card.
“Today he is responsible for what he did,” Tuchel after the game. “Of course, he knows it was a huge mistake. We spoke briefly after the game and things like this can happen.
“At the end of this chain is a decision that brings such a huge disadvantage after 25 minutes. It’s a very, very bad decision from Conor and, of course, he is upset. Everybody was upset in this moment because it almost kills the whole football match.”
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