Washington signed defensive back Jeremiah McKinnon, waiving defensive back Lou Young III with an injury designation to make room.
McKinnon, 24, went undrafted out of Florida International in 2016, signing a three-year, $1.62 million contract as a free agent with the Cowboys. The Cowboys waived him with an injury settlement before the season.
The Titans signed him to their practice squad.
He signed a futures contract with the Cowboys in January before Dallas waived him last week to make room for Justin Durant.
McKinnon made 104 tackles, 14 pass breakups and five interceptions in his four-year college career. He has never played in a regular-season NFL game.