Monaco appear to have already found Mendy's replacement, following the signing of Feyenoord's Terence Kongolo for £12m.
After establishing himself as Tottenham's first-choice right-back, Walker was crowned PFA Young Player of the Year in 2012.
Walker will now join the rest of Guardiola's squad who fly to America on Monday to begin their pre-season tour.
With Aguero and Gabriel Jesus alongside them, arguably, Manchester City have one of the most frightening front lines in world football.
The French outfit have accepted City's bid and the left back is expected to travel to Manchester to undergo a medical and agree personal terms.
Walker completed his £54m switch from Spurs to Manchester City yesterday and is determined to prove to Guardiola that he is a perfect fit for his style of play.
The English top flight can now boast the most expensive back five in history in Walker, Luiz, John Stones, Eliaquim Mangala and Shkodran Mustafi.
Mendy is rated as one of the best players of the current generation in his position and would certainly add a lot of quality to Guardiola's side. Last summer the Juventus defender was repeatedly linked with a move away from Turin, but it never felt like he'd actually leave, but was rather using clubs including Manchester City and Chelsea to help cement his status in Italy. Unfortunately, they haven't been successful so far.
City finished third last year.
"Perhaps that flirting didn't go down too well with some, because there seems to be a crack in the relationship between Bonucci and Juventus, and there's regular doubts published via the Italian media".
After a disappointing season Pep and City are looking to transform the fortunes of the club quickly.
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