The Chilean, keeping City's midweek Champions League away trip to Dynamo Kiev in mind, handed debuts to five youngsters in the cup tie at Stamford Bridge.
Newcastle United legend Shearer cited the example of Barcelona stars Luis Suarez, Neymar and Lionel Messi and Real Madrid ace Cristiano Ronaldo to blast Pellegrini's team selection which eventuated in a second-half drubbing at the hands of Guus Hiddink's strong Chelsea team.
He said on the BBC's Match of the Day: "I don't get the talk of resting players, City are and want to be a very big club, they want to be on the global stage, they have got more resources, more finances than anyone, can virtually buy who they want, so to moan and complain that they have got too many fixtures at this stage of the season, they knew they was going to be in four competitions at the start of the season so why moan.
"I never see Suarez, Messi, Neymar, Ronaldo, these are the best players in the world, I never see these guys wanting to be left out, these guys are never left out or want to be rested for us it seems a big issue in our country.
'I think players are now happy to be rested and have a weekend off, that's in our game now more than it has ever been."