The Oakland Raiders announced the release of cornerback David Amerson on Monday.

As Field Yates of ESPN noted, Amerson's "$5.5 million base salary for 2018 would have become guaranteed if he were on the roster this Wednesday."

Amerson, 26, has spent the past three seasons with the Raiders, appearing in 35 games for the team and registering 140 tackles and six interceptions. In his six games in 2017, however, he earned a 39.7 grade from Pro Football Focus, a dismal mark.

He missed nine games with a foot sprain, though even when he was on the field, his play was inconsistent at best.

The move makes cornerback a major position of need for Oakland this offseason. Matt Schneidman of the Mercury News described it as the team's top need to address, noting that "the Raiders' cornerbacks were largely detrimental to the team this season. The position is easily Oakland's weakest spot on either side of the ball."

The Raiders finished 26th in pass defense last season, giving up 241 yards per game through the air. A healthy Gareon Conley, the team's first-round pick last year, should provide a boost. But with Amerson gone and veteran Sean Smith a candidate to be released—he's due $8.2 million next year and $8.7 million in 2019, per Spotrac.com, but can be released with no salary-cap hit—the Raiders could have several vacancies at the position.

Jon Gruden and company could seek to address the position in the draft or in free agency, depending on how much cap space they are able to free up. With players like Trumaine Johnson, Malcolm Butler, Bashaud Breeland, Aaron Colvin, Kyle Fuller, Rashaan Melvin, E.J. Gaines, Morris Claiborne and Patrick Robinson expected to hit free agency, the Raiders should have options on the market.