Pep Guardiola is still "so angry" with Kyle Walker over the full-back's three-match Champions League suspension.

Walker was sent off for lashing out at Andre Silva in the 82nd minute of City's 2-1 defeat to RB Leipzig in the group stage, with the Premier League champions having already secured qualification into the last 16.

City appealed against the England international's suspension, but it was upheld, with Walker missing the last-16 tie against Sporting CP and the first leg of the quarter-finals, with Guardiola's side surely heading for the last eight after winning the first leg 5-0.

The Premier League leaders are short of options in defence for the second leg at the Etihad Stadium on Wednesday. Ruben Dias is set to miss the next month due to a hamstring problem while Nathan Ake is not yet ready to return from injury, and Joao Cancelo is unwell.

John Stones and Aymeric Laporte are Guardiola's senior options at centre-back, while Oleksandr Zinchenko would seem the most viable option at left-back.

Guardiola said he does not know who will fill in at right-back, as he vented his frustration at Walker.

"He deserved it. Kyle Walker deserved the three," Guardiola said during a news conference when asked about City's failure to win their appeal.

"When one player does this stupid thing he deserves the three games, I'm sorry. I'm not so kind to Kyle in this kind of action.

Kyle Walker has been a key performer for Manchester City

"I'm still so angry with him, so angry. He knows it. It's not necessary to discuss that [with him].

"He's so important, Kyle for us. Did you see the game he played against United? But in Leipzig, we've qualified already, 75, 80 minutes to make this kind of action? So he deserves the three games.

"The club appealed, I did not agree. They had to do it because in other cases that were quite similar it was just two games but he deserved it. Hopefully he learns for the future."

One academy option who could be called upon is Luke Mbete, with the 18-year-old defender set to be included in City's squad.

"He's trained with us for a long time, the application is so high, a guy who wants to learn," Guardiola said.

"Still young but tomorrow he'll be with the squad and maybe we will need him, we will see."

Fernandinho, however, was namechecked as a possible option to slot into the defence, either at right-back or centre-back.

There has been talk of Fernandinho moving into a coaching role, yet Guardiola still wants to keep the Brazilian in his squad if possible.

"I would love [to offer him a new contract]," Guardiola said.

"I'm so glad to have him he's an incredible captain and player. I have a feeling now at 36, 37, he struggled a little bit coming back from holidays but now he's getting his rhythm.

Fernandinho has been utilised as Rodri's back-up this season

"For him he doesn't care, he will play against Peterborough. Other players his age wouldn't want to play there in cold weather, but he wants to help to give rest to Rodri. At the end of the season Txiki [Begiristain, City's director of football] and the club have to decide."

Kevin De Bruyne, meanwhile, is risking a suspension should he play and Guardiola may omit the midfielder.

"He's maybe not [going to start]," Guardiola said with a laugh. "We will see."