The Lions cut Brown on Saturday, Justin Rogers of The Detroit News reports.
Brown entered the NFL as an undrafted rookie in 2017 but didn't suit up for a game. He had an outstanding collegiate career, however, with 236 receptions for 4,024 yards and 21 touchdowns over his last three seasons. If he can't find another team, he'll likely land on the practice squad.
Brown signed a contract with the Lions on Saturday.
Brown spent the 2017 season on the Cowboys' practice squad and now comes to Detroit in hopes of winning one of the last roster spots at wide receiver.
Brown was waived Wednesday by the Cowboys, Rob Phillips of the team's official site reports.
Brown, who went undrafted out of Richmond last April, spent the 2017 season on Dallas' practice squad and was then signed to a reserve/future contract in January. However, it seems he's no longer a part of the team's plans. Brown will now be subject to the league's waiver system and will become a free agent if he goes unclaimed.