Mendy is set to make his first appearance in two months in City's League Cup semi-final, second leg against Burton Albion on Wednesday.
The English champions hold an unprecedented 9-0 lead from the first leg over the team from League One - English football's third tier - so the tie is over as a contest.
Therefore, Guardiola wants to use the match to blood youngsters and give more game time to players in need of minutes.
Mendy falls into that latter category, having suffered a knee injury following a 3-1 derby victory over Manchester United on November 11.
It required treatment in Barcelona for the French World Cup winner and comes after he missed eight months of football last season with an anterior cruciate ligament injury.
Mendy's injury absences have caused Guardiola a headache with no other natural left-back in City's expensively assembled squad.
Fabian Delph, Oleksandr Zinchenko and Aymeric Laporte have all deputised in that role, but the return of the attacking thrust offered by Mendy will be a huge boost to City's challenge on four fronts in the second half of the season.
"I miss him a lot," said Guardiola. "I have a feeling he can give us something extra and hopefully in the last part of the season, we can use him.
"When he pushes from the outside, he is unstoppable and especially in the last third. He is so clever.
"It's not simply cross to cross, it's clever when he does these kinds of actions."
- De Bruyne to start -
While Mendy is only likely to be a substitute as he begins his comeback, Kevin De Bruyne will start at the 6,000-capacity Pirelli Stadium.
The Belgian played his first full 90 minutes of the season in Sunday's 3-0 win at Huddersfield and City's star midfielder has only started twice in the Premier League so far.
Having suffered two separate knee injuries this campaign, De Bruyne is short of games and Guardiola wants him up to speed with tougher tests to come in the Premier League, Champions League, FA Cup and the League Cup final next month.
Phil Foden and goalkeeper Arijanet Muric will also start while five teenagers -- Felix Nmecha, Luke Bolton, Iker Pozo, Ian Carlo Poveda and Taylor Richards -- are in the first-team squad for the first time.
"Some players need rhythm and are going to play," said Guardiola.
"The guys who've had a lot of games will rest. They will do what they need to be fit, but the ones who've not played too much or are back from long-term injuries are going to play.
"We are going to play some youngsters and some will be on the bench. Two or three will play and two, three or four will be on the bench, but Kevin is going to play.
"We start the game with 9-0, which is unusual for a semi-final, but the approach is to improve every single game. It can help us to improve what we want to do."