The Senegal striker, who is West Ham’s top scorer this season with 12 goals, was forced off during last week’s 1-1 draw with Stoke City with a thigh strain and Allardyce is wary of exacerbating the problem.
Allardyce told Sky Sports News HQ: “He may be back before the end of the season he may not, we will just have to be very careful with his thigh strain and make sure we do not get a recurrence. We will not be risking him at 95% fitness – we would have to be sure there was no problem before we risked him.
“It leaves us short in goal-scoring options because Andy Carroll and Sakho are our two leading scorers this season. I’m expecting Carlton Cole will come in and play a big role.”
Allardyce admits he is baffled by City’s recent slump in form but acknowledges it will be a hard to get something out of this weekend’s game.
He said: “I’m very surprised that City have lost four away games on the trot. That’s a huge shock to everyone in football because of the huge amount of talent that they have in their squad.
“But like ourselves they just don’t seem to be able to find a way to win at the moment. I watched them play against Crystal Place and Palace had to defend brilliantly after they went ahead and City are normally exceptionally good at breaking down defences, but they have not been able to manage it.
“At home they are normally very good and we know how tough it is going to be and how hard it is to get something there. But they are struggling in terms of results.
“We want to hit the 50-point mark or better. That will ensure we finish higher in the Premier League than we have done since promotion.”
Watch Manchester City v West Ham before Newcastle v Tottenham live on Super Sunday this weekend. Coverage starts at 12:30pm, Sky Sports 1 HD.