Belotti was one of the most sought-after forwards in Europe after starring in Serie A with 26 goals last season, but he has struggled to repeat that form, netting only nine league goals this term and failing to fire Italy to the World Cup.
But ahead of going up against Belotti as AC Milan boss, Gattuso - who briefly coached the forward at Palermo - has highlighted his "desire to improve" as key in the years to come.
"Two or three years ago, I said that he had impressed me the most since Shevchenko, but now he is going through a difficult time," Gattuso told a pre-match news conference.
"When he is well, he has great physical strength and he is a complete player. He plays well and is impressive in the air. In recent years, he has done important things.
"He is a good guy, with a good head on his shoulders and that is what I liked most. I worked with him for only 20 days, but I remember them with pleasure. If a player has those qualities and that desire to improve, results will come."
Milan themselves need a goalscorer, having netted just twice in their last four matches, but Gattuso is not overly concerned and has not sought to spark talk of further interest in Belotti.
"Reading the newspapers, I see the talk that we have scored few goals," he said. "That's true, but I'm not worried because we create a lot of chances.
"We do have to achieve more - we are 10th for goals scored - but the important thing is that we are getting there. I'm happy with our mentality, with how we sacrifice ourselves and with how we are as a team."
On facing a "tough" Torino side, he added: "If we do not go to Turin in the right frame of mind, we risk making a fool of ourselves."