Massimiliano Allegri believes Juventus already have a squad capable of achieving their objectives but says the club could still enter the transfer market.
In the off-season the Turin giants lost Andrea Pirlo, Arturo Vidal and Carlos Tevez, key figures as Juve claimed their fourth successive Scudetto and reached the Champions League final in 2014-15.
"In terms of the transfer market we've already discussed things with the club, we talked about strategy and evaluations," said Allegri.
"Don't ask me for names, surnames, types of players, because I won't speak about that. What I will say is that in a squad which is already competitive, we can only include players who will improve us.
"Apart from all that, I'm not the driving force behind it, because I don't deal with the transfer market.
"That said, the January transfer window is long, because when the window is open there's always instability.
"Fortunately we have a very competitive squad, which only a select few players could improve."
"First of all, Zaza has grown a lot and is doing well at Juventus. I don't understand why he would leave, and why there's this talk," he added.
"He's a player with great quality, who has improved a lot and is important for us. It's right that he stays with us."
