Stevan Jovetic is set to finally make his Manchester City comeback by the end of January.
The Montenegro international striker, 24, has suffered from calf and hamstring injuries, as well as illness, during what has been a stop-start City career since his 24 million pound move from Fiorentina in July.
He has not featured since limping off in the 2-0 Capital One Cup win over Newcastle in October and had been pencilled in to be a substitute for December’s tie against Leicester in the same competition only to suffer a virus and then sustain a third injury of the season.
With both sidelined, City have been down to two fit strikers -- Edin Dzeko and Alvaro Negredo -- and Pellegrini believes Jovetic would have been a natural deputy for Aguero, who has a calf problem.
He added: "For the player, it is very bad news that he cannot play. [I think that he] was the best chance to replace Aguero when he was injured. But things happen and we must be optimistic for the future and suppose Stevan will play in the second half of the season."
Jovetic has made only three starts for City, just one of those in the Premier League.
Meanwhile, with Arsenal's Theo Walcott ruled out of the rest of the season and the World Cup with a knee injury, City's James Milner could be an alternative to start on the right wing for England.
Pellegrini championed his cause, adding: "Milner is a very useful player. I trust a lot in him -- I think he is a very good player."