Blues are looking at a number of options ahead of the winter transfer window opening, the Chilean boss has explained.
Manchester City have a shortlist of centre-forward targets ahead of the January transfer window.
Edin Dzeko joined Stevan Jovetic and Sergio Aguero in the treatment room after picking up an injury during the warm-up ahead of Saturday’s win at Leicester City.
He is unlikely to feature again this year, while Jovetic is expected to take over two weeks to recover from the hamstring injury he suffered during a cameo in last week’s Champions Leaguie victory in Rome.
With Aguero sidelined until the end of January and Alvaro Negredo on loan at Valencia, Pellegrini was forced to select 18-year-old Spaniard Jose Angel Pozo up front at the King Power Stadium.
However, City could soon boast a fourth striker again.
They have been linked with Swansea’s Wilfried Bony and Villa’s Christian Benteke as well as Newcastle’s Papiss Cisse.
“The transfer window in January is always an option for all the teams, and also for us,” Pellegrini said.
“We decided to let Alvaro Negredo go because we had options to replace him in January.
“Of course, we have three strikers injured, it is an option for us to analyse, as we have important options and we will try to and one player we can’t replace is Sergio.
“We’ll see first of all options, we have options in January, after that we will find an option for our team, we will see if the other club wants to sell the player. It is not easy in January to make a transfer.”
Pozo played for 74 minutes at Leicester on his first Premier League start for City, but was overshadowed by the potent Frank Lampard’s winner.
Pellegrini, however, has reservations about starting him up front and might now be forced into fielding a strikerless side for Saturday’s visit of Crystal Palace.
“Pozo can play but it is not a position he normally plays,” Pellegrini conceded.
“So we must try to find another way to play because I think that our main striker (Aguero) will be out for at least one month more so we have to see what is the best decision to take for the team.”
Lampard, 36, boasted a goalscoring ratio akin to a striker during his Chelsea heyday and played in a more advanced role at Leicester than Yaya Toure, himself an insatiable goalscorer last season.
As well as Dzeko’s injury, Vincent Kompany’s return from injury resulted in the City captain aggravating the hamstring that initially sidelined him.
Like United, City are recording several muscle injuries and Pellegrini is baffled by the sudden rise in City’s casualties.
“It’s difficult to know why we have so many,” the Chilean added.
“I think that the players play too many games in the year, especially the players in big teams, because when they have the international break they must continue playing with the national squad, so it’s an important amount of games.
“Last year, I remember that we played nine games in December and nine games in January.
“It’s difficult for players to keep a high-pace in the Premier League.
“In the Premier League, the pace and the intensity of every game is very high so one of the reasons is we play too many games in the year, especially at the end of the year.
“It can also be a problem with the pitch, as it can be hard.
“There are different reasons to know.”