Fabio Cannavaro has endorsed the capture of Gonzalo Higuain but says it will be difficult for Juventus to win the Champions League without Paul Pogba.
Juve spent big to recruit Higuain, last season's top scorer in Serie A, from Napoli as a replacement for striker Alvaro Morata, who was re-signed by Real Madrid.
But the departure of France international Pogba to Manchester United for a world-record fee has left a void in midfield that head coach Massimiliano Allegri may struggle to fill against top opposition, according to Cannavaro.
"Juve certainly reinforced themselves - they have a deep, complete squad and I think Higuain is stronger than Morata, but winning the Champions League is incredibly tough," ex-Bianconeri defender Cannavaro was quoted by Gazzetta dello Sport.
"Juve have acquired the habit of winning in Italy, but in Europe things are different and it's no easy task to replace Pogba."
"He guaranteed not just goals and technique but also a physicality that [Miralem] Pjanic doesn't have," Cannavaro added, referring to the arrival of the Bosnia-Herzegovina international from Roma.
"As well as the strength of Higuain, I like the drive and personality provided by Dani Alves on the wing. But the team must be evaluated according to the new balance that Allegri will manage to develop. It'll take a bit of time."
Juve reached the final of the Champions League during Allegri's first season at the helm, losing 3-1 to Barcelona in the 2015 final.
They went out at the hands of Bayern Munich in the round of 16 last term, having finished second behind Manchester City in Group D.
And Cannavaro knows the importance of Juve topping the pool in order to secure a favourable passage into the knockouts.
"Winning the groups stage is going to be important for two reasons," he said.
"Firstly because it will set them up against a second-placed team in the last 16, which presumably is not going to be one of the favourites. And secondly, because winning helps to win."