Both players scored 49 goals between them before injuries brought a halt to their output in recent weeks - Aguero missed five games with a hamstring problem and Negredo has been suffering with a shoulder inhjury.
Pellegrini is considering playing the two together in Sunday's FA Cup quarter-final against Wigan in the hope of building momentum for the Champions League trip to Barcelona next Tuesday, where City must overturn a 2-0 deficit.
The City boss said: "In that moment (earlier in the season), it was very productive for the team - and I hope in the future it can be again.
"But in other moments when Sergio was injured, Negredo played very well at that time. (Edin) Dzeko and Negredo, Dzeko and Sergio have also done it. It's important to have important strikers."
Aguero, City's top scorer this term with 26, returned to action after a five-game lay-off with a hamstring problem to play 58 minutes in the Capital One Cup final last weekend.
Pellegrini said: "I also think it was very useful for Sergio to play the 50 or 60 minutes with his national squad.
"He played the same amount of minutes in the final so every match he will
Negredo has gone six games without a goal and Pellegrini believes his performances have been affected not only by fitness problems but also a loss of confidence.
He said: "Maybe it is a little bit of all of those.
"It starts with a problem with his shoulders. Strikers also live from the goals they score.
"But I trust absolutely that Alvaro will return to his normal performance. He will continue scoring goals, the same as Edin."