West Ham are on the verge of signing the Italy international, much to the relief of Slaven Bilic, who has been attempting to sign a striker all summer.
The Hammers met the release clause of AC Milan striker Bacca, but the Colombian decided to stay in Milan to try to get the club back into Europe.
Bilic has made no secret of his attempts to sign a striker this summer, and is in desperate need of a new front man after Andy Carroll and Andre Ayew were ruled out of action for six weeks and two months respectively due to injuries.
Speaking ahead of West Ham's match against Manchester City, Slaven Bilic said: "With the Zaza situation it looks very likely to happen and should happen today.
"As far as I know the deal is agreed between clubs. The personal terms are also agreed and he is due in London today, so we hope it will be done.
"It’s very positive and it’s a boost. We’ve been trying for a long time now to get a top-quality striker and he was always mentioned".
Is Zaza a good signing for the Hammers?