Kyle Walker was sent off for a kick.
Kyle Walker was sent off in the loss to RB Leipzig that hurt Manchester City, according to the boss.
City were assured of top spot in Group A before they lost in Germany.
Walker was sent off for hacking out at Silva with eight minutes to go and will face a suspension.
" Kyle Walker is an important player for us and it is unnecessary to lose him like this," said Guardiola afterwards.
I hope he learns from this. The red card hurts us in the round of 16.
It's a red card. I'm not going to say what happened in the dressing room.
After Jesse Marsch was sacked last weekend, Silva and Dominik Szoboszlai opened the scoring.
Walker was sent off for kicking Silva on the back of the leg after Riyad Mahrez headed in for City.
We lacked rhythm in the first half. We had problems in contact and they have a really good team.
The second half was better than the first. We played to win the game, but we made a few mistakes and they punished us. We lost. Thank you to Leipzig.
We made a good group stage. We qualified with one game left from a tough group, so I am more than satisfied with the performance in every game.
Midfielder Phil Foden was taken off as a precautionary measure because of an ankle issue, while defender Nathan Ake had a back problem, which was also picked up by City.
