Oakland Raiders wide receiver Antonio Brown was not present at the team's first day of organized team activities on Tuesday, according to MJ Acosta of NFL Network.

It's worth noting that these workouts are voluntary, and Brown was an active participant at the first round of offseason workouts.

The Raiders acquired Brown in a trade with the Pittsburgh Steelers back in March, sending a third-round pick and a fifth-rounder to the Steelers in exchange for the Pro Bowler.

Brown, who had spent the first nine years of his NFL career with Pittsburgh, is coming off of a 2018 campaign in which he hauled in 104 receptions for 1,297 yards and a league-leading 15 touchdowns en route to his sixth straight Pro Bowl appearance.

He then asked the Steelers for a trade as a result of a confrontation with quarterback Ben Roethlisberger and a souring relationship with head coach Mike Tomlin and Pittsburgh's front office in general.

The 30-year-old, who played his collegiate football at Central Michigan, was originally selected by the Steelers in the sixth round (195th pick overall) of the 2010 NFL Draft.

He barely played during his rookie season, logging just 16 catches for 167 yards, but the following year, Brown made his first Pro Bowl after catching 69 passes for 1,108 yards and a couple of scores.

Since then, Brown has been one of the best wide outs in the league, leading the NFL in receptions and receiving yards on two separate occasions. He also earned four consecutive First-Team All-Pro selections from 2014 through 2017.

The Raiders won just four games this past season.