It's not, because he's been good for us ever since he signed. His overall stats prove it (closing in on 1 goal per 2 games).
He's had the toughest time of all of our strikers, because Conte - for some time - has showed undeservingly little faith in him. But when you play him, consistently, he will supply the goals. The stats show it.
Then there's all the other stuff he does for the team. He's been a great team player for us ever since he joined.