Gaines, 27, is a former sixth-round pick of the Rams back in 2014. The Rams traded him to the Bills as part of the Sammy Watkins deal.
Gaines played out the final year of his four-year, $2,327,672 contract and made a base salary of $690,000 for the 2017 season before signing with the Browns for 2018. After one year in Cleveland, Gaines signed a one-year contract worth up to $3.6 million with the Bills this past March.
The Bills placed Gaines on injured reserve a few weeks ago.
In 2018, Gaines appeared in six games for the Browns and recorded 13 tackles, one interception and three pass defenses.