Johnson is still expected to seek a trade from Cleveland.
Earlier this week, agent Kristin Campbell confirmed to Cleveland.com that she no longer was representing Johnson.
Johnson, who has attended mandatory Browns workouts during the offseason, said last month that there was nothing the team could do to change his mind about wanting a trade.
In June 2018, Johnson signed a three-year, $15.6 million extension with the Browns. He is under contract through the 2021 season.
A third-round draft choice of the Browns in 2015, Johnson has rushed for 1,286 yards over four seasons. He fell behind rookie Nick Chubb on the depth chart last season, and the team signed Kareem Hunt, who will miss the first eight games of 2019 for violating the NFL's personal conduct policy.
ESPN's Jake Trotter contributed to this report.