Smith was set to make $8.25 million in base salary in 2018, and his release comes with no dead money against Oakland's cap.
Smith, who turns 31 in July, signed an eye-popping four-year, $40 million contract - $20 million guaranteed - prior to the 2016 season, but never lived up to his billing.
Still, given the Raiders' subpar cornerbacks group, Smith was probably the best one among them the second half of the season. This after being 109th in passer rating allowed in Weeks 1-11.
After Ken Norton Jr. was replaced as defensive playcaller by John Pagano, Smith was used more to his strengths. Smith contributed to a lackluster Oakland secondary, and though he intercepted Cowboys quarterback Dak Prescott twice in one game, was largely inconsistent on the year.
The Silver and Black have released cornerback Sean Smith, a source told NFL Network Insider Ian Rapoport. Plus, Carrie is a free agent. Smith was benched early in his Raiders career and failed to lock down a cornerback position that has since been given to last year's first round rookie, Gareon Conley.
He has appeared in 100 games (70 starts) in his career with the Green Bay Packers, Cincinnati Bengals, New York Giants and Raiders.