Kompany limped off during the 3-0 win over Southampton on Sunday, but Pellegrini says 'we will see' when it comes to questions about his availability for the trip to the Stadium of Light.
Kompany has yet to be ruled out of tomorrow night's trip to the North East to take on Sunderland at the Stadium of Light.
The City boss told reporters: "We’ll know this afternoon exactly what Vincent has. He has an injury to his hamstring - we'll see how long it’ll be.”
City are still without the trio of David Silva, Aleksandar Kolorov and Edin Dzeko - though the latter is expected to return to the side in the coming days, and could be available for the visit of Everton on Saturday evening.
Pellegrini also said that Matija Nastasic has suffered an injury setback. When assessing his defensive options, he said: “Unfortunately Nastasic has a muscle injury in his thigh. I don’t think he will be able to work for a week or more.
“We have Boyata working well, we have Demichelis and we have Sagna. We have options and we’ll see which two of them will play.”
Eliaquim Mangala is suspended for tomorrow's game after he was dismissed for a second bookable offence during Sunday's win on the South coast.
City don't have a great record against Sunderland having lost on each of their last visits to the Stadium of Light, and Pellegrini is expecting another difficult game following on from the Black Cats draw against league leaders Chelsea.
“Sunderland is a tough team to play against – they defend well. We hope we will have more luck there this year."
After the weekend's results, Pellegrini's side closed the gap to Chelsea to six points, and said the defending champions were never out of the title race.
He added: “We were never out of the fight for the title. We have to play a lot more games and then are too many points to play for."