Dallas coach Jason Garrett said the release of Patmon on Tuesday was about performance and not related to any off-the-field issues.
A former undrafted free agent in his second year, Patmon was cut despite the Cowboys (4-9) possibly being without starter Morris Claiborne on Saturday night against the New York Jets (8-5). Claiborne has a hamstring injury.
Patmon was inactive for two games midseason but regained a spot in the lineup. He had 15 tackles and six pass breakups, the third-most on the team.
The Cowboys also released linebacker Darius Eubanks from the practice squad.