Toure returned to the starting lineup from injury this afternoon, creating one and scoring another in a man of the match display as City increased their title credentials with a 2-0 win over Crystal Palace at Selhurst Park.
The Ivorian was taken off just after the hour mark due to his recent absence, and Pellegrini admitted that he didn't know whether he would be 100% fit for next weekend's crucial match against Everton.
"We hope, but we don't know. You saw him, he was very important for both goals. Yaya only worked with the team the last two days, that's why he didn't play more than 60 minutes. But he's a very important player for us," Pellegrini told reporters.
"He's a top player, and in the 10 days he was injured he doesn't lose too much on his football condition. So he just played 60 minutes because he was very tired, but he's a very important player for us.
"The most important thing is that we don't depend on just one player. We have a squad and in every game I try to choose the best players that will fit for that moment. Having Yaya fit will be very important."
The Premier League title is now in Manchester City's hands due to their superior goal difference and game in hand over Liverpool, who lost 2-0 to Chelsea today.