The Bills activated wide receiver John Brown from the Covid-19/reserve list Friday.
Brown was deemed to have been a close contact with running back T.J. Yeldon, who tested positive last Sunday. The Bills activated Brown from injured reserve before Monday's win at New England and moved him to the Covid-19 list.
Safety Josh Thomas and running back Christian Wade also were removed from the Covid-19 list. They were returned to the practice squad.
The team signed wide receiver J.J. Nelson and cornerback Duke Thomas to the practice squad.
Nelson, 28, has appeared in 58 career games, all but two with the Arizona Cardinals. He played two games with the Raiders last season. He was released by the San Francisco 49ers in early September with an injury settlement for a knee injury. He has 85 receptions for 1,475 yards and 11 touchdowns, with six coming in 2016.
The Bills will be the ninth pro team for Thomas, 26, since he went undrafted out of Texas in 2016. That includes a stint in the CFL and the AAF. He most recently was with the Arizona Cardinals, who waived him in August.
The Bills released offensive lineman Marquel Harrell, linebacker Deon Lacey and cornerback Lafayette Pitts from the practice squad.