Sergio Aguero in contention for Man City vs. Chelsea - Manuel Pellegrini

MANCHESTER -- Manuel Pellegrini admits he faces a decision whether to rush Sergio Aguero back into Manchester City's starting XI for Sunday's clash with Premier League champions Chelsea.

City's 32-goal top scorer last season has only played 27 minutes of football since the Copa America final and Pellegrini would prefer to give the striker a gradual introduction.

But he said that he could be tempted to field Aguero, who was granted four weeks' off in July and then came off in the bench in Monday's 3-0 win over West Bromwich Albion, against Jose Mourinho's side.

"Sergio worked the whole week without any problems," Pellegrini said in a news conference. "He is not 100 percent fit because it is better for the player to do a long preseason but now we are already in the Premier League and Sergio doesn't have any problems."

While Aguero was a substitute, Wilfried Bony was City's starting striker at the Hawthorns and the former Swansea player's Ivory Coast teammate Yaya Toure was among their scorers.

The midfielder came off with a groin problem but Pellegrini confirmed he will be fit to face Chelsea.

"Yaya is OK," he said. "It was just a precaution the other day."

But City will be without two other midfielders as Fabian Delph, who has a hamstring injury, has been joined on the sidelines by Fernando.

"Fernando has a groin problem," Pellegrini explained. "He could not play the first game and he will not be ready for this one also."

City are waiting to discover if left-back Gael Clichy will be fit to return

"He started yesterday [Thursday] working with the squad," Pellegrini said. "We will see tomorrow if he is in the squad list for Sunday. He is working as normal."