Per Ed Bouchette of the Pittsburgh Post-Gazette, the Steelers had already determined they were going to explore trade possibilities for their disgruntled wide receiver.
Brown's trade request came after he posted a cryptic message on Twitter, thanking Steelers fans for their support over the past nine seasons:
The saga involving the Steelers and Brown seemingly began leading up to a Week 17 game against the Cincinnati Bengals. Brown refused to practice following a dispute with quarterback Ben Roethlisberger and was benched for the game, per Bouchette and Gerry Dulac.
Steelers president Art Rooney II told Dulac last month it would be "hard to envision" Brown returning to the team next season.
Per NFL Network's Ian Rapoport, Brown will meet with Rooney in person to discuss the situation.
If the Steelers do trade Brown, ESPN.com's Jeremy Fowler cited one NFL general manager who said the team would likely want a first-round draft pick in return.
Brown, 30, has the highest cap hit among wide receivers for 2019 ($22.2 million), per Over the Cap. He remains one of the most productive players in the NFL.
Last season marked the sixth straight year in which Brown recorded more than 100 receptions and 1,200 yards. He also led the league and set a career high with 15 touchdown receptions.