The summer arrival from Lille has battled for form so far this season.
"David is in good shape. He is very professional, and can move no matter where he is on the pitch," said Spalletti.
Spalletti believes that it is self-confidence that is lacking for David at the moment.
"It's a shame he doesn't have enough confidence to show his qualities right now, but he can be a top-class finisher. He has what it takes to be an incredible goalscorer," he added.
The striker's contract with Juventus extends until the summer of 2030.