Depends what you mean by "jack shit". Right now it's not his best of moments. It's not a secret. Last season, mainly Conte, killed any confidence he had. It's not easy being the team's best scorer and then get benched for Borriello for no particular reason. The man needs a goal badly, and while he's not been scoring lately, it's pretty easy to notice how the team tends to play better with him upfront. His movement gets the best out of Vucinic and MVP, mainly Pirlo.
I know what you're going to say. How is he the perfect substitute when he doesn't score? Every striker has moments like these, but as shown in his previous seasons, he'll start banging them goals again.