Yaya Toure has been left of Manchester City's squad for the side's Champions League group stage fixtures.
The midfielder will not be travelling to any of City's European games as they line up against Borussia Monchengladbach, Celtic and Barcelona in the coming months.
In accordance with Uefa's rules, City could not include more than 17 overseas players in their squad with Toure missing out as Guardiola turned to a number of the club's other options.
Guardiola has instead chosen to include the likes of Leroy Sane and Ilkay Gundogan, who are yet to play for the club, skipper Vincent Kompany, who is recovering from groin and thigh operations which kept him out of Euro 2016, and 19-year-old forward Kelechi Iheanacho.
Toure's future at the club had been called into question following Guardiola's arrival, with Inter Milan registering interest in the midfielder.
But the Ivory Coast international never expressed any genuine interest in leaving City throughout the summer and intends to see out his contract, which expires in 2017.
However, Guardiola's decision to leave the player out from the European squad suggests Toure will only play a peripheral role at City now.
He has played just the once this season, in the second leg of the Champions League play-off tie against Steaua Bucharest, when City were already 5-0 up from the first game.
Despite featuring in all the club's trophy wins since signing for City in 2010, the player's days look to be numbered.
Clubs can change three players after the group stage but the 33-year-old will not be able to play up until then.
City's first Champions League fixture takes place on Tuesday 13 September against Borussia Monchengladbach.
Manchester City's Champions League squad:
Claudio Bravo, Willy Caballero
Bacary Sagna, Vincent Kompany, Pablo Zabaleta, Aleksandar Kolarov, Gael Clichy, John Stones, Nicolas Otamendi
Fernando, Raheem Sterling, Ilkay Gundogan, Jesus Navas, Kevin De Bruyne, Fabian Delph, Leroy Sane, David Silva, Fernandinho
Nolito, Sergio Aguero, Kelechi Iheanacho
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