Arnette was already on injured reserve with a thumb injury.
Arnette, 23, was a three-year starter at Ohio State and earned second-team All-Big Ten honors last season before being selected by the Raiders with the No. 19 pick in the draft.
Arnette signed a projected four-year, $13,418,540 rookie contract that includes a $7,318,938 signing bonus. The contract includes a fifth-year for the Raiders to pick up for the 2024 season.
In 2020, Arnette has appeared in three games for the Raiders and recorded 12 total tackles and one pass defense.