The 23-year-old has enjoyed a successful first season in the Premier League since joining the Black Cats last summer, and Tardelli has praised the powerful winger.
"He is a good boy. He wants to work because he knows he needs to learn many things. He is strong physically and I think he will be for us a good player. Surely, he is the future, but maybe it is possible also this time," Tardelli told reporters.
Ireland meet Bosnia-Herzegovina in a friendly on Saturday.