Pastorello admits that Chelsea attempted to sign the Italian in January, but was knocked back by Inter's new owners.
Conte viewed Candreva as a direct replacement for Oscar, who departed for China in the same month.
And Pastorello hopes he can renew the Blues' interest this summer by contacting the Serie A club.
"This past January, Chelsea wanted to sign Candreva. They needed a replacement for Oscar and Antonio would have been a good one," Pastorello told Rai Sport.
"However, he had just joined Inter and [owners] Suning do not want to sell their best players. I don't know if he'll stay, I'll talk to [directors] Ausilio and Sabatini."