Speaking to the Wigan Evening Post, Bruce said: "Zaki just needs a goal to get him going again.
"As a manager, I have to decide how long to give it, can he get us a goal? It's a really difficult one, but I'm paid to make decisions like that.
"You'll find that if natural goalscorers aren't scoring, they beat themselves up mentally, and a little bit of their confidence goes.
"If a goal bounces in off Zaki's backside, he would probably be capable of getting another six goals before the end of the season. We'll see how he does.
"Zaki is a bit of a one-off, he can either be on a real high or feeling really down, he needs to find an equilibrium."
It is likely that Zaki will be partnered up front by Columbian forward Hugo Rodallega as his fellow Egyptian, Mido will be dropped for the visit to the Stadium of Light as Bruce shakes up his front line.
The Middlesbrough loanee has been well below par during his stint with the Latics and Bruce is expected to give Rodallega a chance from the start after a string of impressive substitute displays.
"We've got the option of Rodallega now, he's indicated in recent games that he's nearly ready to play from the start," added Bruce.
"He's trained with us for five or six weeks now, he can give us a little bit of spark."
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