Djokovic competed in only 11 tournaments this year as he missed his title defence at Melbourne Park at the start of the year and was also unable to play in the North American swing - including the US Open - due to his unvaccinated Covid-19 status.
The 21-time Grand Slam winner, though, had some excellent results when he was allowed to play as he won Wimbledon, the ATP Masters Italian Open, the Astana Open and Tel Aviv Open before going on to lift the season-ending ATP Finals without losing a match.
Alcaraz, meanwhile, won the US Open and surged to No 1 in the ATP Rankings, having also won two ATP Masters 1000 titles and two ATP 500 events.
The pair met at the Madrid Open earlier this year and it was the teenager who emerged victorious in three tight sets.
Ferrero feels Alcaraz needs more matches against the best in the business if he is to take his tennis to the next level.
"We need him [Djokovic]," the former world No 1 told Eurosport.
"I think for Carlos to improve his tennis he needs to play against one of the best in the history. Of course Rafa [Nadal] is there to play against him and Novak, we need him.
"In Madrid Carlos played against Novak and he increased his level to try to win the match, so that's what we need, to play in the Slams against him, I think it's very important for Carlos to improve."
With Djokovic set to return to the Australia Open next year after his three-year visa ban was lifted, there is potential for a first Grand Slam clash with Alcaraz.
Ferrero is pleased that the tennis great will play at Melbourne Park next year.
"I think after the US Open, which he couldn't play, he was very focused to show himself that he is able to win almost everything that he played, we saw again that he's able to do it," the Spaniard said.
"He presented himself to all the players that he's going to be there and that he has the possibility to play in Australia, I think he's very happy about it and I think the rest of the players as well.
"Carlos and I were talking about that we're happy to see Novak there because if you want to win the Australian Open you have to win against the best, and of course it's good news. But of course it didn't surprise me at all that he won in Turin."