The Rams waived Jackson on Tuesday, per the NFL's transaction log.
Jackson gave himself a shot to make the roster by catching three of five targets for 48 yards in the Rams' preseason finale. However, the 23-year-old was unable to secure a spot after being sidelined for nearly two weeks of training camp with a leg injury. The Syracuse product made the Rams' initial 53-man roster to start the 2020 campaign, but he remained inactive all season. He is a likely candidate to join the Rams' practice squad if he goes unclaimed on waivers.