The 19-year-old winger impressed last season by scoring nine goals for the Reds as they eventually finished second to Premier League winners Manchester City.
Asked which England player he thought would be their star man in Brazil, the former midfielder tipped Sterling to return from South America with his reputation enhanced.
He told the club's official website: "I think it will be the player who impressed me most last season - Raheem Sterling. The kid has got the world at his feet.
"He did ever so well last season, he came on a lot. He added goals and his all-round play was superb."
Hamannn won the 2005 Champions League with the Reds.