Juventus legend Claudio Gentile insists his former club must improve defensively if they are to challenge for honours.
The Old Lady are expected to sign a new centre-back before the window closes, a move that the 1982 World Cup winner sees as a necessity.
"The defence certainly needs reinforcing," the ex-Italian Under-21 boss told Radio Sportiva.
"All winning sides need to start from the back and the defence has been Juve's Achilles' heel in recent campaigns."
The Bianconeri have been linked with Diego Lugano of Fenerbahce and Chelsea stopper Alex in recent weeks.
"I'd prefer Lugano out of those two," continued Gentile.
Juve spent €15.5m on Leonardo Bonucci last summer, but the Italian international had his problems.
"Unfortunately he disappointed," the veteran added. "If the club decide to sell him then it is because he didn't deliver what was expected.
"He's young so he could be given another chance, but you have to take into account that Juve can't wait for too long "
Bonucci has been linked with a move to Zenit St Petersburg that could see Portuguese centre-back Bruno Alves arrive in the other direction.