Leonard, 25, was a second-round pick of the Rams in 2007. He started seven games as a rookie but only played two games last season and didn't have a start.
Leonard could be a good fit for the Bengals because he can be a pass-catching fullback and a backup running back.
Plus, he is considered a good character player and someone who could work well with quarterback Carson Palmer. Leonard is a 6-foot-1, 229-pounder who played at Rutgers.
The 6-3, 300-pound Harris will be joining his sixth team. He was a fourth-round choice of the Steelers in 2006. He has been with the Browns, Bills, Saints and Bengals. He has started one game in his NFL career.