Riddick, 29, is a former sixth-round pick of the Lions back in 2013. He was in the third year of his four-year, $12.3 million contract and set to make base salaries of $2.7 million and $3.2 million over the final two years of the agreement when the Lions released him.
The Broncos later signed Riddick to a contract, but he was placed on injured reserve with a shoulder injury coming out of the preseason.
He recently signed a one-year deal with the Raiders before being cut by the team.
In 2018, Riddick appeared in 14 games for the Lions and rushed for 171 yards on 40 carries (4.3 YPC) to go along with 61 receptions for 384 yards receiving and no touchdowns.