Mayowa, 26, signed as a restricted free agent from Oakland in 2016. He led the team with six sacks in 2016, starting six of 13 games played.
Last season, Mayowa had just one sack in 14 games, including two starts.
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The Cowboys need as much cap space as possible after handing DeMarcus Lawrence the franchise tag, which will cost $17.143 million. The team is also hopeful to land a long-term deal with All-Pro guard Zack Martin this off-season.
In related news, the Cowboys released defensive tackle Joe Vellano, who joined the team’s practice squad late last season.