Nasri has figured prominently in the past month and was particularly impressive in last weekend's 4-1 derby destruction of Manchester United at the Etihad Stadium, in which he scored his second goal of the season.
On the whole Nasri's performances since his £24million move from the Gunners in 2011 have been mixed and an underwhelming first half of last season led to some severe criticism from former manager Roberto Mancini.
Mancini even said at one point that he could "punch" the 26-year-old, such was the Italian's frustration with the player's erratic form.
But Nasri appeared to have turned that around with some strong displays in the closing weeks of the 2012-13 campaign and that resurgence has carried over into the Pellegrini era.
Pellegrini said: "I don't talk about what happened in the past but in this moment Nasri is playing very well.
"I talk often with him because I know how much he can do as a big player.
"His performances I am always evaluating and he knows he must play the way I know he can.
"If he doesn't do it maybe we have other choices but Nasri is absolutely committed with the team and with me, and with all the other players.
"We hope we will see a great Nasri the whole year.
"He is a player that has great technical quality and he works in the game a lot - not only in the last 25 metres.
"He runs back and makes passes. He is a very creative player."
Another player hoping to reassert himself this season, but for different reasons, is defender Micah Richards.
The City youth product was a key component of the 2011-12 Premier League title success playing at right-back but his last campaign was ravaged by injury.
The 25-year-old made just eight appearances last term due to ankle and knee problems.
In his absence Pablo Zabaleta established himself as first-choice right-back but Richards is now fit again and ready to challenge for a place.
It had been suggested Richards could move to a place in the centre, due to Zabaleta's brilliance, but both player and manager are focusing on the wide role.
Richards said in an interview this week he was concentrating on right-back and Pellegrini agrees, saying: "At centre-back we have (Vincent) Kompany, (Matija) Nastasic, (Joleon) Lescott and Martin Demichelis.
"Maybe in an emergency he can play there but his natural position is right-back.
"At right-back we have just two players, Zabaleta and Micah Richards. I think it is the best use for us."
Richards made an impressive first appearance of the season after overcoming his latest injury setback in Tuesday's 5-0 Capital One Cup win over Wigan.
Pellegrini said: "He came back from a long injury and he played really well.
"He is an important defender. When he is fit he will have options to play because Pablo played the last six games. I think it is good for whole team."