Cox, 27, was a free agent bust signing made by the Chargers last season. Cox received a four-year contract worth $20 million that included $10.25 million guaranteed from San Diego, but was released after one season.
He recently signed with the Ravens, but was among their final roster cuts. Since then Cox has worked out for the Buccaneers,
Last year, Cox appeared in all 16 games, but totaled just 38 tackles and an interception. Pro Football Focus rated Cox as the No. 104 cornerback in the league out of 110 qualifying players last year.
Damian Williams, 26, spent his first four seasons with the Titans, before attempting to make the Dolphins 53-man roster this year. His best season came in 2011, when he recorded 45 catches for 592 yards and five touchdowns.
Kyle Williams, 27, is a former sixth-round pick of the 49ers. He spent three years with the team before he was placed on waivers and later claimed by the Chiefs in 2013. He later re-signed with the team but was placed on injured reserve at the end of August and recently released with an injury settlement.
Last year, he appeared in 10 games for Kansas City and caught 12 passes for 113 yards receiving.