Baltimore had one opening on the 53-man roster following last week's trade of Bryant McKinnie to the Dolphins, so no additional move needs to be made.
Scott, 29, comes aboard after running for 1,035 yards and four touchdowns in four seasons with Cincinnati. He also was a key contributor in the return game over his first two seasons and has 73 career kick returns for 1,787 yards and a touchdown.
The Ravens also worked out former Cardinals tailback Beanie Wells, who reportedly was hurt in his tryout.
Scott should help provide insurance and a breather for Ray Rice and Bernard Pierce, who both have been dealing with injuries this year. The Ravens had been going with two running backs since cutting Shaun Draughn on Oct. 10.
Scott was selected in the sixth round of the 2009 draft out of Abilene Christian. He is coming off a torn ACL that limited him to two games in 2012. He began 2013 on the Bengals' physically unable to perform list before being released Sept. 17.