Clichy has an ankle injury, while Delph continues to recover from a hamstring problem sustained on the pre-season tour in Australia.
The South American quartet of Sergio Aguero, Pablo Zabaleta, Martin Demichelis and Fernandinho are all fit, although the manager will make a late call on whether to include them given their late return to pre-season.
Samir Nasri will also be available following brief bouts of illness.
Ahead of the new season Pellegrini promised the Club would stick to their principles of attacking and free-flowing football, saying: "I think the style with this group will continue as it has in the last two seasons.
"It's not fortune that we have been the team that scores most goals, we didn't win the title but we were an attacking team, maybe we need to be more competitive or play with more concentration at times."
The manager, who has penned a new contract at the Club, is looking for a tighter defensive performance, adding that 38 goals conceded in the league last season was too many and that, "we should not be conceding more than 30, 31 to have a chance to win the title."
Pellegrini has been impressed, if not surprised, by Raheem Sterling's early impact and believes the youngster can only improve.
He added: "(He has been) very very good, the media have been talking about the price, but he's an English player, young, with quality, speed and technical ability. He will improve every year playing with the likes of Yaya, Silva, Kun, they will help him."
Pellegrini was also open to the prospect of more additions to the squad before the transfer window closes.
"We'll see, we have until the end of month for more players," he reflected. "It's not easy to bring a player here, not only because of the amount of money but because we need special players, we'll see in the next weeks."