The Italy international was one of the stars of the first half of the 2012-13 campaign, but his progress halted after the winter break as he struggled to hit his best form.
A number of recent reports even suggested that Milan could cash in on the 20-year-old if a good offer comes in and Boban thinks a transfer is not out of the question.
"El Shaarawy needs to improve a lot. He is too predictable at the moment. Everybody knows what's going to happen when he cuts inside," he told Sky Sport Italia.
"I get the idea that Milan see him as a good player, but nothing more than that. I get the feeling that they are already considering selling him. [Adriano] Galliani has already said that he's not unsellable, so I think they will sell him if the price is right."
El Shaarawy's current contract with Milan runs until June 2018.