Amerson, 26, played in just six games (all starts) last season and missed the final eight because of a foot injury. He made 33 starts in all for the Raiders in three seasons, intercepting six passes with 46 passes defensed.
He had signed a four-year contract extension before the 2016 season. Amerson's $5.5 million base salary for 2018 would have become guaranteed if he were on the team's roster Wednesday.
Monday was the first day teams could begin releasing veterans ahead of the 2018 season.
A prime candidate to be cut this offseason, Amerson was asked before the season finale if he expected to return to Oakland in 2018.
"I don't know, man," Amerson told ESPN on Dec. 27. "You never know with this league. You never know. It's all about: What have you done for me lately?"
And with how poorly his season went in Oakland?
"That's what I'm saying," he said.
Still, Amerson, a former second-round pick of Washington who was claimed off waivers by the Raiders in 2015, hoped to return.
But after missing two total games in his first three NFL seasons, concussion, shoulder and foot injuries wreaked havoc with his 2017 campaign. In fact, it was against the Kansas City Chiefs on Oct. 19 when Amerson was in the locker room, getting his upper body checked out by team staff, that he noticed his lower body was hurting.
"Right before halftime, they were shooting up my shoulder and I told the trainers, 'Yo, something's wrong with my foot,'" Amerson recalled. "It felt like a burning sensation and it felt weak."
Amerson would not take the field again.
And while he said he was not diagnosed with a Lisfranc fracture, nor could he recall a specific play in which the foot was injured, Amerson said he did have ligament damage.
"It couldn't take the impact," Amerson said. "I couldn't push or cut."
Per Pro Football Focus, Amerson allowed a 156.3 passer rating, ranking last in the NFL among 159 cornerbacks with at least 40 coverage snaps.