Johnson might have been a salary-cap casualty if he had not restructured his contract.
Johnson would have been owed nearly $9 million in 2021, of which just $2.1 million was guaranteed, before agreeing to the restructured deal.
Johnson ran for 691 yards and six touchdowns last season on 147 carries. He played in only 12 games, missing three with a concussion and one while he was on the reserve/COVID-19 list.
When the Texans traded for Johnson a year ago, the deal was done by former general manager and head coach Bill O'Brien, who was fired in October. At the time, Johnson was coming off the lowest production of his career and given the keys to the Houston backfield.
Johnson's best season came in 2016, for the Cardinals, when he was selected to his only Pro Bowl and was a first-team All Pro after setting career bests in rushing yards (1,239), rushing touchdowns (16), receptions (80), receiving yards (879) and yards from scrimmage (2,118, which led the NFL).
The Texans released pass-catching running back Duke Johnson last week.
ESPN's Adam Schefter, Jeremy Fowler and Sarah Barshop contributed to this report.