"It's not like if Zaza plays less, he has to leave. He's doing well at the moment because he scored important goals... and has grown a lot."
Juve bought the 24-year-old Zaza, who has played seven times for Italy, for 18 million euros from Sassuolo last year
He has been linked in media reports with English Premier League clubs including Arsenal, Tottenham Hotspur and West Ham United.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Rugani, 21, returned to Juventus from Empoli last year.
"A great player is required to improve the team. It is difficult to find a great player in January," Allegri said, referring to this month's transfer window.
Second-placed Juventus play Udinese, who are 12th in Serie A, on Sunday.
(Reporting by Silvia Recchimuzzi in Gdynia, editing by Ed Osmond)
