Winfrey was one of the standout performers for the Cowboys at Tuesday's joint practice with the Rams, Tommy Yarrish of the team's website reports.
Signed in June after earning All-UFL honors with Birmingham this spring, Winfrey beat a double team to stuff Kyren Williams for a loss in the backfield during a red-zone drill. Osa Odighizuwa, Mazi Smith (knee) and Solomon Thomas are expected to be the primary members of the rotation at defensive tackle for Dallas, but Winfrey's making a case to carve out a role as well.