Manchester City boss Pep Guardiola has blasted "stupid" Kyle Walker for picking up a Champions League suspension that has left him without a right-back for the round-of-16 second-leg tie with Sporting Lisbon on Wednesday.

Guardiola said he did not agree with City's decision to appeal the three-game ban that will also rule Walker out of the quarterfinal first leg.

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Walker was shown a red card for kicking Andre Silva during the 2-1 defeat to RB Leipzig in the final group game in December.

Guardiola said he has still not forgiven the England defender, particularly after the other right-back in the squad, Joao Cancelo, was ruled out of the game against Sporting because of illness.

"He deserved it [the suspension], he deserved the three, he did a stupid thing," Guardiola told a news conference on Tuesday.

"I'm not kind to Kyle for this kind of action. I'm still so angry with him. He knows it, it's not necessary. He deserved it. The club appealed but I did not agree. Hopefully he learned."

With City leading 5-0 from the first leg in Portugal, Guardiola has the luxury of being able to rest midfielder Kevin De Bruyne for the second leg at the Etihad Stadium, with the Belgian midfielder one yellow card away from suspension.

However, the Spanish coach said he is yet to solve the problem at right-back caused by Walker's suspension.

"I don't know [who will play]," Guardiola said.

"[John] Stones? Fernandinho maybe? We'll speak with some players, we are going to speak about the academy.

"We don't have many players, just 14 available. Of course we had an incredible result in the first leg but football is unpredictable, red cards, quality of opponent.

"We'll take a top side as much as possible. Not many alternatives but we will do the best team possible to win the game."

City are still in the hunt for the Premier League title, Champions League and FA Cup; a treble that would emulate Manchester United's achievement in 1999.

Guardiola has played down the chances of lifting all three trophies, but goalkeeper Ederson said he believes the squad can do it.

"Definitely," Ederson said.

"We know how difficult it is. That is very demanding on the entire group. We know how difficult it is but we have the quality to do this.

"We've shown this previously and we're showing it at the moment. I think we're fully capable of meeting this achievement."