According to Derek Bodner of The Athletic, Brown said, "I think another high level free-agent is required [to win a championship]. I think we have the ability to attract one."
With Ben Simmons and Joel Embiid leading the way, the Sixers returned to the playoffs this season for the first time since 2011-12.
Philly advanced to the second round, where it was eliminated by the Boston Celtics in five games.
Simmons is the possible Rookie of the Year, and Embiid was an All-Star with averages of 22.9 points, 11.0 rebounds and 3.2 assists per game.
Philly also has some good supporting pieces in Robert Covington, Dario Saric and Markelle Fultz.
Fultz could be one of the biggest keys to Philly taking the next step in 2018-19, as he missed all but 14 games due to injury after being the No. 1 overall pick in the 2017 NBA draft.
Adding another big piece to the fold would be huge for the Sixers' championship aspirations, though, and Brown seemed to hint toward who Philadelphia may be targeting after telling Bodner, "We don't have to turn this into calculus. It's quite clear."
Provided he opts out of his contract as expected, Cleveland Cavaliers superstar LeBron James will be the top player on the market.
In March, Kevin O'Connor of The Ringer reported that the 76ers were one of the teams on LeBron's free-agent list along with the Cavs, Los Angeles Lakers and Houston Rockets.
Even if the Sixers don't land James, other possibilities include Oklahoma City Thunder forward Paul George, New Orleans Pelicans center DeMarcus Cousins and Los Angeles Clippers center DeAndre Jordan.
With a young, talented core in place, the 76ers represent an ideal situation for an All-Star free agent looking to chase a championship in 2018-19 and beyond.