The Philadelphia 76ers guard, who is gearing up for his third full season in the league, has been heavily criticised for his inability to shoot the basketball, particularly late in games. Last season he averaged 16.9 points per game before really struggling in the playoffs where his scoring average dipped to just 13.9.
Pierce says Simmons, the 2018 Rookie of the Year, has already proven himself to be a one-of-a-kind athlete, but with a little work on his jump shot there's a real chance he could become one of the most dominant players in the NBA.
"If Ben can get a respectable three-point shot, he would easily be a top five player in this league," Pierce told ESPN. "He doesn't have to be a Steph Curry, just a guy with a respectable jumper who looks to shoot it often and keep the defence honest.
"He's a great rebounder, he's a great passer and a dynamic athlete. He can pretty much do everything else, so if he gets a jumper that means his scoring average will go up and we're going to be talking about him as being one of the best all-round players in the NBA.
"He'll be averaging 18-20 points per game, eight-nine rebounds and nine-10 assists. He has the skillset to average a triple double and only Russell Westbrook can do that right now."
Simmons, 23, is still in the early stages of his NBA career, but Pierce says it's critical the Australian develops his skills sooner rather than later as the Sixers are looking to cash in with their talented squad which features the likes of Joel Embiid, Al Horford, Josh Richardson and Tobias Harris.
"A player of his caliber has to continue to grow and find ways to continually become better," Pierce told ESPN. "What is he going to do to improve and help his team get to the next stage?
"If [Philadelphia] is going to go far in the playoffs, and eventually win a championship, he's going to be the key. He can't be limited, especially in the playoffs, like we've seen in the past.
"If he can continue to improve on his skills, it will be interesting to see his trajectory into super stardom."
The Sixers get their 2019-20 campaign underway on October 23 when they host the Boston Celtics at Wells Fargo Center.