Those placed on the reserve/COVID-19 list either have tested positive for COVID-19 or are a close contact to someone who tested positive.
On Friday, the Patriots canceled practice after a positive COVID-19 test. Later that day, the club placed center James Ferentz on the reserve/COVID-19 list.
The Patriots host the Denver Broncos on Sunday (1 p.m. ET, CBS), and Ferentz, Mason and Rivers will not play in the game. Michel wouldn't have played anyway as he is on injured reserve.
Starting defensive tackle Byron Cowart is also on the reserve/COVID-19 list and will not play in the game.
The NFL's rules for 2020 accounted for teams having to fill voids like this, starting with an increased practice squad of 16 players, in addition to two waiver exceptions when moving players between the practice squad and active roster as part of a "standard elevation." Teams also have the option to elevate players as specific COVID-19 replacements for players who land on the reserve/COVID-19 list.
Along those lines, the Patriots elevated offensive lineman Caleb Benenoch from their practice squad Saturday as part of a "standard elevation."
In addition, defensive end Rashod Berry, receiver Isaiah Zuber and defensive tackle Nick Thurman have been elevated as specific COVID-19 replacements for Sunday's game.